diff --git a/ApacheThrift.nuspec b/ApacheThrift.nuspec
index 7c8e300..a5629e8 100644
--- a/ApacheThrift.nuspec
+++ b/ApacheThrift.nuspec
@@ -19,14 +19,14 @@
      the "Thrift" project.
   2. nuget setApiKey <your-api-key>
   3. nuget pack ApacheThrift.nuspec -Symbols -SymbolPackageFormat snupkg
-  4. nuget push ApacheThrift.0.16.0.nupkg -Source https://api.nuget.org/v3/index.json
+  4. nuget push ApacheThrift.0.17.0.nupkg -Source https://api.nuget.org/v3/index.json
   -->
 
 <package xmlns="http://schemas.microsoft.com/packaging/2013/05/nuspec.xsd">
   <metadata>
     <id>ApacheThrift</id>
-    <version>0.16.0</version>
-    <title>Apache Thrift 0.16.0</title>
+    <version>0.17.0</version>
+    <title>Apache Thrift 0.17.0</title>
     <authors>Apache Thrift Developers</authors>
     <owners>Apache Software Foundation</owners>
     <license type="expression">Apache-2.0</license>
@@ -36,7 +36,7 @@
     <description>
       Contains runtime libraries from lib/netstd for netstandard2.0 framework development.
     </description>
-    <repository type="GitHub" url="https://github.com/apache/thrift" branch="release/0.16.0" />
+    <repository type="GitHub" url="https://github.com/apache/thrift" branch="release/0.17.0" />
     <tags>Apache Thrift RPC</tags>
   </metadata>
   <files>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8ffb528..e5f93cd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -28,7 +28,7 @@
 
 # PACKAGE_VERSION is used by cpack scripts currently
 # Both thrift_VERSION and PACKAGE_VERSION should be the same for now
-set(thrift_VERSION "0.16.0")
+set(thrift_VERSION "0.17.0")
 set(PACKAGE_VERSION ${thrift_VERSION})
 
 project("thrift" VERSION ${PACKAGE_VERSION})
diff --git a/Thrift.podspec b/Thrift.podspec
index addea6b..4e3abbd 100644
--- a/Thrift.podspec
+++ b/Thrift.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name          = 'Thrift'
-  s.version       = '0.16.0'
+  s.version       = '0.17.0'
   s.summary       = "Apache Thrift is a lightweight, language-independent software stack with an associated code generation mechanism for RPC."
   s.description   = <<-DESC
 The Apache Thrift scalable cross-language software framework for networked services development combines a software stack with a code generation engine to build services that work efficiently and seamlessly between many programming languages.
@@ -10,6 +10,6 @@
   s.author        = { 'Apache Thrift Developers' => 'dev@thrift.apache.org' }
   s.ios.deployment_target = '9.0'
   s.osx.deployment_target = '10.10'
-  s.source        = { :git => 'https://github.com/apache/thrift.git', :tag => 'v0.16.0' }
+  s.source        = { :git => 'https://github.com/apache/thrift.git', :tag => 'v0.17.0' }
   s.source_files  = 'lib/swift/Sources/*.swift'
 end
diff --git a/appveyor.yml b/appveyor.yml
index 8b791e4..5fe31db 100755
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -19,7 +19,7 @@
 
 # build Apache Thrift on AppVeyor - https://ci.appveyor.com
 
-version: '0.16.0.{build}'
+version: '0.17.0.{build}'
 
 shallow_clone: true
 
diff --git a/bower.json b/bower.json
index 46873c7..6ddfb38 100644
--- a/bower.json
+++ b/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "thrift",
-  "version": "0.16.0",
+  "version": "0.17.0",
   "homepage": "https://github.com/apache/thrift.git",
   "authors": [
     "Apache Thrift <dev@thrift.apache.org>"
diff --git a/compiler/cpp/src/thrift/generate/t_netstd_generator.cc b/compiler/cpp/src/thrift/generate/t_netstd_generator.cc
index ff22274..d3f3a1b 100644
--- a/compiler/cpp/src/thrift/generate/t_netstd_generator.cc
+++ b/compiler/cpp/src/thrift/generate/t_netstd_generator.cc
@@ -51,6 +51,7 @@
     : t_oop_generator(program)
 {
     (void)option_string;
+    use_net6_features = false;
     suppress_deepcopy = false;
     add_async_postfix = false;
     use_pascal_case_properties = false;
@@ -81,6 +82,9 @@
         else if (iter->first.compare("no_deepcopy") == 0) {
           suppress_deepcopy = true;
         }
+        else if (iter->first.compare("net6") == 0) {
+          use_net6_features = true;
+        }
         else if (iter->first.compare("async_postfix") == 0) {
           add_async_postfix = true;
         }
@@ -159,6 +163,7 @@
     pverbose("- serialize ....... %s\n", (is_serialize_enabled() ? "ON" : "off"));
     pverbose("- wcf ............. %s\n", (is_wcf_enabled() ? "ON" : "off"));
     pverbose("- pascal .......... %s\n", (use_pascal_case_properties ? "ON" : "off"));
+    pverbose("- net6 ............ %s\n", (use_net6_features ? "ON" : "off"));
     pverbose("- no_deepcopy ..... %s\n", (suppress_deepcopy ? "ON" : "off"));
     pverbose("- async_postfix ... %s\n", (add_async_postfix ? "ON" : "off"));
 }
@@ -170,16 +175,16 @@
 
     // check for reserved argument names
     if( is_arg_name && (CANCELLATION_TOKEN_NAME == name))
-	{
-		name += "_";
-	}
+    {
+        name += "_";
+    }
 
     // un-conflict keywords by prefixing with "@"
     if (netstd_keywords.find(tmp) != netstd_keywords.end())
     {
         return "@" + name;
     }
-	
+
     // no changes necessary
     return name;
 }
@@ -302,14 +307,31 @@
 }
 
 
+void t_netstd_generator::pragmas_and_directives(ostream& out)
+{
+    if( use_net6_features) {
+      out << "#nullable enable                 // requires C# 8.0" << endl;
+    } else {
+      out << "#nullable disable                // suppress C# 8.0 nullable contexts (we still support earlier versions)" << endl;
+    }
+
+    // this one must be first
+    out << "#pragma warning disable IDE0079  // remove unnecessary pragmas" << endl;
+
+    out << "#pragma warning disable IDE0017  // object init can be simplified" << endl
+        << "#pragma warning disable IDE0028  // collection init can be simplified" << endl
+        << "#pragma warning disable IDE1006  // parts of the code use IDL spelling" << endl
+        << "#pragma warning disable CA1822   // empty " << DEEP_COPY_METHOD_NAME << "() methods still non-static" << endl;
+
+    if( ! use_net6_features) {
+        out << "#pragma warning disable IDE0083  // pattern matching \"that is not SomeType\" requires net5.0 but we still support earlier versions" << endl;
+    }
+    out << endl;
+}
+
+
 void t_netstd_generator::start_netstd_namespace(ostream& out)
 {
-    out << "#nullable disable                // suppress C# 8.0 nullable contexts (we still support earlier versions)" << endl
-        << "#pragma warning disable IDE0079  // remove unnecessary pragmas" << endl
-        << "#pragma warning disable IDE1006  // parts of the code use IDL spelling" << endl
-        << "#pragma warning disable IDE0083  // pattern matching \"that is not SomeType\" requires net5.0 but we still support earlier versions" << endl
-        << endl;
-
     if (!namespace_name_.empty())
     {
         out << "namespace " << namespace_name_ << endl;
@@ -346,7 +368,7 @@
         namespaces += "using System.Runtime.Serialization;\n";
     }
 
-    return namespaces + endl;
+    return namespaces;
 }
 
 string t_netstd_generator::netstd_thrift_usings() const
@@ -360,7 +382,7 @@
         "using Thrift.Transport.Server;\n"
         "using Thrift.Processor;\n";
 
-    return namespaces + endl;
+    return namespaces;
 }
 
 void t_netstd_generator::close_generator()
@@ -393,6 +415,7 @@
     reset_indent();
     out << autogen_comment() << endl;
 
+    pragmas_and_directives(out);
     start_netstd_namespace(out);
     generate_netstd_doc(out, tenum);
 
@@ -437,8 +460,9 @@
     }
 
     reset_indent();
-    out << autogen_comment() << netstd_type_usings() << endl;
+    out << autogen_comment() << netstd_type_usings() << endl << endl;
 
+    pragmas_and_directives(out);
     start_netstd_namespace(out);
 
     out << indent() << "public static class " << make_valid_csharp_identifier(program_name_) << "Constants" << endl;
@@ -680,7 +704,7 @@
         return;
     }
 
-    if (ttype->is_map() || ttype->is_set() || ttype->is_list())
+    if (ttype->is_container())
     {
         if( collected_extension_types.find(key) == collected_extension_types.end())
         {
@@ -702,6 +726,10 @@
                 t_list* tlist = static_cast<t_list*>(ttype);
                 collect_extensions_types(tlist->get_elem_type());
             }
+            else
+            {
+                throw "compiler error: unhandled container type " + ttype->get_name();
+            }
         }
 
         return;
@@ -732,8 +760,11 @@
     }
 
     reset_indent();
-    out << autogen_comment() << netstd_type_usings() << endl;
+    out << autogen_comment() << netstd_type_usings()
+        << "using Thrift.Protocol;" << endl
+        << endl << endl;
 
+    pragmas_and_directives(out);
     start_netstd_namespace(out);
 
     out << indent() << "public static class " << make_valid_csharp_identifier(program_name_) << "Extensions" << endl;
@@ -745,7 +776,11 @@
     {
         out << indent() << "public static bool Equals(this " << iter->first << " instance, object that)" << endl;
         scope_up(out);
-        out << indent() << "if (!(that is " << iter->first << " other)) return false;" << endl;
+        if( use_net6_features) {
+            out << indent() << "if (that is not " << iter->first << " other) return false;" << endl;
+        } else {
+            out << indent() << "if (!(that is " << iter->first << " other)) return false;" << endl;
+        }
         out << indent() << "if (ReferenceEquals(instance, other)) return true;" << endl;
         out << endl;
         out << indent() << "return TCollections.Equals(instance, other);" << endl;
@@ -759,38 +794,42 @@
         out << endl << endl;
 
         if(! suppress_deepcopy) {
-            out << indent() << "public static " << iter->first << " " << DEEP_COPY_METHOD_NAME << "(this " << iter->first << " source)" << endl;
+            out << indent() << "public static " << iter->first << nullable_field_suffix(iter->second) << " " << DEEP_COPY_METHOD_NAME << "(this " << iter->first << nullable_field_suffix(iter->second) << " source)" << endl;
             scope_up(out);
             out << indent() << "if (source == null)" << endl;
             indent_up();
             out << indent() << "return null;" << endl << endl;
             indent_down();
 
+            string suffix("");
             string tmp_instance = tmp("tmp");
             out << indent() << "var " << tmp_instance << " = new " << iter->first << "(source.Count);" << endl;
             if( iter->second->is_map())
             {
                 t_map* tmap = static_cast<t_map*>(iter->second);
-                string copy_key = get_deep_copy_method_call(tmap->get_key_type(), needs_typecast);
-                string copy_val = get_deep_copy_method_call(tmap->get_val_type(), needs_typecast);
+                string copy_key = get_deep_copy_method_call(tmap->get_key_type(), true, needs_typecast, suffix);
+                string copy_val = get_deep_copy_method_call(tmap->get_val_type(), true, needs_typecast, suffix);
                 bool null_key = type_can_be_null(tmap->get_key_type());
                 bool null_val = type_can_be_null(tmap->get_val_type());
 
                 out << indent() << "foreach (var pair in source)" << endl;
                 indent_up();
-                out << indent() << tmp_instance << ".Add(";
-                if( null_key)
-                {
-                    out << "(pair.Key != null) ? pair.Key" << copy_key << " : null";
+                if( use_net6_features) {
+                    out << indent() << tmp_instance << ".Add(pair.Key" << copy_key;
+                    out << ", pair.Value" << copy_val;
                 } else {
-                    out << "pair.Key" << copy_key;
-                }
-                out << ", ";
-                if( null_val)
-                {
-                    out << "(pair.Value != null) ? pair.Value" << copy_val << " : null";
-                } else {
-                    out << "pair.Value" << copy_val;
+                    out << indent() << tmp_instance << ".Add(";
+                    if( null_key) {
+                        out << "(pair.Key != null) ? pair.Key" << copy_key << " : null";
+                    } else {
+                        out << "pair.Key" << copy_key;
+                    }
+                    out << ", ";
+                    if( null_val) {
+                        out << "(pair.Value != null) ? pair.Value" << copy_val << " : null";
+                    } else {
+                        out << "pair.Value" << copy_val;
+                    }
                 }
                 out << ");" << endl;
                 indent_down();
@@ -801,24 +840,28 @@
                 if (iter->second->is_set())
                 {
                     t_set* tset = static_cast<t_set*>(iter->second);
-                    copy_elm = get_deep_copy_method_call(tset->get_elem_type(), needs_typecast);
+                    copy_elm = get_deep_copy_method_call(tset->get_elem_type(), true, needs_typecast, suffix);
                     null_elm = type_can_be_null(tset->get_elem_type());
                 }
                 else // list
                 {
                     t_list* tlist = static_cast<t_list*>(iter->second);
-                    copy_elm = get_deep_copy_method_call(tlist->get_elem_type(), needs_typecast);
+                    copy_elm = get_deep_copy_method_call(tlist->get_elem_type(), true, needs_typecast, suffix);
                     null_elm = type_can_be_null(tlist->get_elem_type());
                 }
 
                 out << indent() << "foreach (var elem in source)" << endl;
                 indent_up();
-                out << indent() << tmp_instance << ".Add(";
-                if( null_elm)
-                {
-                    out << "(elem != null) ? elem" << copy_elm << " : null";
+                if( use_net6_features) {
+                    out << indent() << tmp_instance << ".Add(elem" << copy_elm;
                 } else {
-                    out << "elem" << copy_elm;
+                    out << indent() << tmp_instance << ".Add(";
+                    if( null_elm)
+                    {
+                        out << "(elem != null) ? elem" << copy_elm << " : null";
+                    } else {
+                        out << "elem" << copy_elm;
+                    }
                 }
                 out << ");" << endl;
                 indent_down();
@@ -864,8 +907,9 @@
     f_struct.open(f_struct_name.c_str());
 
     reset_indent();
-    f_struct << autogen_comment() << netstd_type_usings() << netstd_thrift_usings() << endl;
+    f_struct << autogen_comment() << netstd_type_usings() << netstd_thrift_usings() << endl << endl;
 
+    pragmas_and_directives(f_struct);
     generate_netstd_struct_definition(f_struct, tstruct, is_exception);
 
     f_struct.close();
@@ -915,7 +959,7 @@
         // if the field is required, then we use auto-properties
         if (!field_is_required((*m_iter)))
         {
-            out << indent() << "private " << declare_field(*m_iter, false, "_") << endl;
+            out << indent() << "private " << declare_field(*m_iter, false, true, "_") << endl;
         }
     }
     out << endl;
@@ -930,7 +974,7 @@
         if (is_required)
         {
             has_required_fields = true;
-    }
+        }
         else
         {
             has_non_required_fields = true;
@@ -1041,7 +1085,7 @@
                 {
                     out << ", ";
                 }
-                out << type_name((*m_iter)->get_type()) << " " << normalize_name((*m_iter)->get_name());
+                out << type_name((*m_iter)->get_type()) << nullable_field_suffix(*m_iter) << " " << normalize_name((*m_iter)->get_name());
             }
         }
         out << ") : this()" << endl
@@ -1113,7 +1157,7 @@
         // if the field is required, then we use auto-properties
         if (!field_is_required((*m_iter)))
         {
-            out << indent() << "private " << declare_field(*m_iter, false, "_") << endl;
+            out << indent() << "private " << declare_field(*m_iter, false, true, "_") << endl;
         }
     }
     out << endl;
@@ -1146,8 +1190,9 @@
 
     for (m_iter = members.begin(); m_iter != members.end(); ++m_iter) {
         bool needs_typecast = false;
+        string suffix("");
         t_type* ttype = (*m_iter)->get_type();
-        string copy_op = get_deep_copy_method_call(ttype, needs_typecast);
+        string copy_op = get_deep_copy_method_call(ttype, true, needs_typecast, suffix);
 
         bool is_required = field_is_required(*m_iter);
         generate_null_check_begin( out, *m_iter);
@@ -1511,8 +1556,9 @@
     f_union.open(f_union_name.c_str());
 
     reset_indent();
-    f_union << autogen_comment() << netstd_type_usings() << netstd_thrift_usings() << endl;
+    f_union << autogen_comment() << netstd_type_usings() << netstd_thrift_usings() << endl << endl;
 
+    pragmas_and_directives(f_union);
     generate_netstd_union_definition(f_union, tunion);
 
     f_union.close();
@@ -1531,7 +1577,7 @@
 
     out << indent() << "public abstract global::System.Threading.Tasks.Task WriteAsync(TProtocol tProtocol, CancellationToken " << CANCELLATION_TOKEN_NAME << ");" << endl
         << indent() << "public readonly int Isset;" << endl
-        << indent() << "public abstract object Data { get; }" << endl
+        << indent() << "public abstract object" << nullable_suffix() <<" Data { get; }" << endl
         << indent() << "protected " << tunion->get_name() << "(int isset)" << endl
         << indent() << "{" << endl;
     indent_up();
@@ -1542,79 +1588,136 @@
     const vector<t_field*>& fields = tunion->get_members();
     vector<t_field*>::const_iterator f_iter;
 
-    out << indent() << "public override bool Equals(object that)" << endl;
+    out << indent() << "public override bool Equals(object" << nullable_suffix() << " that)" << endl;
     scope_up(out);
-    out << indent() << "if (!(that is " << tunion->get_name() << " other)) return false;" << endl;
+    if( use_net6_features) {
+        out << indent() << "if (that is not " << tunion->get_name() << " other) return false;" << endl;
+    } else {
+        out << indent() << "if (!(that is " << tunion->get_name() << " other)) return false;" << endl;
+    }
     out << indent() << "if (ReferenceEquals(this, other)) return true;" << endl;
     out << endl;
     out << indent() << "if(this.Isset != other.Isset) return false;" << endl;
     out << endl;
-    out << indent() << "switch (Isset)" << endl;
-    scope_up(out);
-    for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter)
-    {
-        bool needs_typecast = false;
-        string copy_op = get_deep_copy_method_call((*f_iter)->get_type(), needs_typecast);
-        out << indent() << "case " << (*f_iter)->get_key() << ":" << endl;
-        indent_up();
-        out << indent() << "return Equals(As_" << (*f_iter)->get_name() << ", other.As_" << (*f_iter)->get_name() << ");" << endl;
+    if(use_net6_features) {
+        out << indent() << "return Isset switch" << endl;
+        scope_up(out);
+        for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter)
+        {
+            bool needs_typecast = false;
+            string suffix("");
+            get_deep_copy_method_call((*f_iter)->get_type(), false, needs_typecast, suffix);
+            out << indent() << (*f_iter)->get_key() << " => Equals(As_" << (*f_iter)->get_name() << ", other.As_" << (*f_iter)->get_name() << ")," << endl;
+        }
+        out << indent() << "_ => true," << endl;
         indent_down();
+        out << indent() << "};" << endl;
+    } else {
+        out << indent() << "switch (Isset)" << endl;
+        scope_up(out);
+        for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter)
+        {
+            bool needs_typecast = false;
+            string suffix("");
+            get_deep_copy_method_call((*f_iter)->get_type(), false, needs_typecast, suffix);
+            out << indent() << "case " << (*f_iter)->get_key() << ":" << endl;
+            indent_up();
+            out << indent() << "return Equals(As_" << (*f_iter)->get_name() << ", other.As_" << (*f_iter)->get_name() << ");" << endl;
+            indent_down();
+        }
+        out << indent() << "default:" << endl;
+        indent_up();
+        out << indent() << "return true;" << endl;
+        indent_down();
+        scope_down(out);
     }
-    out << indent() << "default:" << endl;
-    indent_up();
-    out << indent() << "return true;" << endl;
-    indent_down();
-    indent_down();
-    scope_down(out);
     scope_down(out);
     out << endl;
 
     out << indent() << "public override int GetHashCode()" << endl;
     out << indent() << "{" << endl;
     indent_up();
-    out << indent() << "switch (Isset)" << endl;
-    out << indent() << "{" << endl;
-    indent_up();
-    for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter)
-    {
-        bool needs_typecast = false;
-        string copy_op = get_deep_copy_method_call((*f_iter)->get_type(), needs_typecast);
-        out << indent() << "case " << (*f_iter)->get_key() << ":" << endl;
-        indent_up();
-        out << indent() << "return As_" << (*f_iter)->get_name() << ".GetHashCode();" << endl;
-        indent_down();
-    }
-    out << indent() << "default:" << endl;
-    indent_up();
-    out << indent() << "return (new ___undefined()).GetHashCode();" << endl;
-    indent_down();
-    indent_down();
-    out << indent() << "}" << endl;
-    indent_down();
-    out << indent() << "}" << endl << endl;
-
-    if( ! suppress_deepcopy) {
-        out << indent() << "public " << tunion->get_name() << " DeepCopy()" << endl;
+    if(use_net6_features) {
+        out << indent() << "return Isset switch" << endl;
         out << indent() << "{" << endl;
         indent_up();
+        for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter)
+        {
+            string null_coalesce(is_nullable_type((*f_iter)->get_type()) ? "?" : "");  
+            out << indent() << (*f_iter)->get_key() << " => As_" << (*f_iter)->get_name() << null_coalesce << ".GetHashCode()";
+            if( null_coalesce.size() > 0) {
+              out << " ?? 0";
+            }
+            out << "," << endl;
+        }
+        out << indent() << "_ =>  (new ___undefined()).GetHashCode()" << endl;
+        indent_down();
+        out << indent() << "};" << endl;
+    } else {
         out << indent() << "switch (Isset)" << endl;
         out << indent() << "{" << endl;
         indent_up();
         for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter)
         {
-            bool needs_typecast = false;
-            string copy_op = get_deep_copy_method_call((*f_iter)->get_type(), needs_typecast);
+            string null_coalesce(is_nullable_type((*f_iter)->get_type()) ? "?" : "");  
             out << indent() << "case " << (*f_iter)->get_key() << ":" << endl;
             indent_up();
-            out << indent() << "return new " << (*f_iter)->get_name() << "(As_" << (*f_iter)->get_name() << copy_op << ");" << endl;
+            out << indent() << "return As_" << (*f_iter)->get_name() << null_coalesce << ".GetHashCode()";
+            if( null_coalesce.size() > 0) {
+              out << " ?? 0";
+            }
+            out << ";" << endl;
             indent_down();
         }
         out << indent() << "default:" << endl;
         indent_up();
-        out << indent() << "return new ___undefined();" << endl;
+        out << indent() << "return (new ___undefined()).GetHashCode();" << endl;
         indent_down();
         indent_down();
         out << indent() << "}" << endl;
+    }
+    indent_down();
+    out << indent() << "}" << endl << endl;
+
+    if( ! suppress_deepcopy) {
+        out << indent() << "public " << tunion->get_name() << " " << DEEP_COPY_METHOD_NAME << "()" << endl;
+        out << indent() << "{" << endl;
+        indent_up();
+        if(use_net6_features) {
+            out << indent() << "return Isset switch" << endl;
+            out << indent() << "{" << endl;
+            indent_up();
+            for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter)
+            {
+                bool needs_typecast = false;
+                string suffix("");
+                string copy_op = get_deep_copy_method_call((*f_iter)->get_type(), false, needs_typecast, suffix);
+                out << indent() << (*f_iter)->get_key() << " => new " << (*f_iter)->get_name() << "(As_" << (*f_iter)->get_name() << suffix << copy_op << ")," << endl;
+            }
+            out << indent() << "_ => new ___undefined()" << endl;
+            indent_down();
+            out << indent() << "};" << endl;
+        } else {
+            out << indent() << "switch (Isset)" << endl;
+            out << indent() << "{" << endl;
+            indent_up();
+            for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter)
+            {
+                bool needs_typecast = false;
+                string suffix("");
+                string copy_op = get_deep_copy_method_call((*f_iter)->get_type(), false, needs_typecast, suffix);
+                out << indent() << "case " << (*f_iter)->get_key() << ":" << endl;
+                indent_up();
+                out << indent() << "return new " << (*f_iter)->get_name() << "(As_" << (*f_iter)->get_name() << suffix << copy_op << ");" << endl;
+                indent_down();
+            }
+            out << indent() << "default:" << endl;
+            indent_up();
+            out << indent() << "return new ___undefined();" << endl;
+            indent_down();
+            indent_down();
+            out << indent() << "}" << endl;
+        }
         indent_down();
         out << indent() << "}" << endl << endl;
     }
@@ -1623,11 +1726,11 @@
     out << indent() << "{" << endl;
     indent_up();
 
-    out << indent() << "public override object Data { get { return null; } }" << endl
+    out << indent() << "public override object" << nullable_suffix() <<" Data { get { return null; } }" << endl
         << indent() << "public ___undefined() : base(0) {}" << endl << endl;
 
     if( ! suppress_deepcopy) {
-        out << indent() << "public new ___undefined DeepCopy()" << endl;
+        out << indent() << "public new ___undefined " << DEEP_COPY_METHOD_NAME << "()" << endl;
         out << indent() << "{" << endl;
         indent_up();
         out << indent() << "return new ___undefined();" << endl;
@@ -1663,13 +1766,17 @@
 
 void t_netstd_generator::generate_netstd_union_class(ostream& out, t_struct* tunion, t_field* tfield)
 {
-    out << indent() << "public " << type_name(tfield->get_type()) << " As_" << tfield->get_name() << endl;
+    out << indent() << "public " << type_name(tfield->get_type()) << nullable_field_suffix(tfield) << " As_" << tfield->get_name() << endl;
     out << indent() << "{" << endl;
     indent_up();
     out << indent() << "get" << endl;
     out << indent() << "{" << endl;
     indent_up();
-    out << indent() << "return (" << tfield->get_key() << " == Isset) ? (" << type_name(tfield->get_type()) << ")Data : default(" << type_name(tfield->get_type()) << ");" << endl;
+    out << indent() << "return (" << tfield->get_key() << " == Isset) && (Data != null)"
+        << " ? (" << type_name(tfield->get_type()) << nullable_field_suffix(tfield) << ")Data"
+        << " : default"
+        << (use_net6_features ? "" : ("(" + type_name(tfield->get_type()) + ")"))
+        << ";" << endl;
     indent_down();
     out << indent() << "}" << endl;
     indent_down();
@@ -1681,8 +1788,8 @@
     out << indent() << "{" << endl;
     indent_up();
 
-    out << indent() << "private " << type_name(tfield->get_type()) << " _data;" << endl
-        << indent() << "public override object Data { get { return _data; } }" << endl
+    out << indent() << "private readonly " << type_name(tfield->get_type()) << " _data;" << endl
+        << indent() << "public override object" << nullable_suffix() <<" Data { get { return _data; } }" << endl
         << indent() << "public " << tfield->get_name() << "(" << type_name(tfield->get_type()) << " data) : base("<< tfield->get_key() <<")" << endl
         << indent() << "{" << endl;
     indent_up();
@@ -1691,20 +1798,25 @@
     out << indent() << "}" << endl;
 
     if( ! suppress_deepcopy) {
-        out << indent() << "public new " << tfield->get_name() << " DeepCopy()" << endl;
+        out << indent() << "public new " << tfield->get_name() << " " << DEEP_COPY_METHOD_NAME << "()" << endl;
         out << indent() << "{" << endl;
         indent_up();
         bool needs_typecast = false;
-        string copy_op = get_deep_copy_method_call(tfield->get_type(), needs_typecast);
+        string suffix("");
+        string copy_op = get_deep_copy_method_call(tfield->get_type(), true, needs_typecast, suffix);
         out << indent() << "return new " << tfield->get_name() << "(_data" << copy_op << ");" << endl;
         indent_down();
         out << indent() << "}" << endl << endl;
     }
 
-    out << indent() << "public override bool Equals(object that)" << endl;
+    out << indent() << "public override bool Equals(object" << nullable_suffix() << " that)" << endl;
     out << indent() << "{" << endl;
     indent_up();
-    out << indent() << "if (!(that is " << tunion->get_name() << " other)) return false;" << endl;
+    if(use_net6_features) {
+        out << indent() << "if (that is not " << tunion->get_name() << " other) return false;" << endl;
+    } else {
+        out << indent() << "if (!(that is " << tunion->get_name() << " other)) return false;" << endl;
+    }
     out << indent() << "if (ReferenceEquals(this, other)) return true;" << endl;
     out << endl;
     out << indent() << "return Equals( _data, other.As_" << tfield->get_name() << ");" << endl;
@@ -1735,7 +1847,7 @@
         << indent() << "field.ID = " << tfield->get_key() << ";" << endl
         << indent() << "await oprot.WriteFieldBeginAsync(field, " << CANCELLATION_TOKEN_NAME << ");" << endl;
 
-    generate_serialize_field(out, tfield, "_data", true);
+    generate_serialize_field(out, tfield, "_data", true, false);
 
     out << indent() << "await oprot.WriteFieldEndAsync(" << CANCELLATION_TOKEN_NAME << ");" << endl
         << indent() << "await oprot.WriteFieldStopAsync(" << CANCELLATION_TOKEN_NAME << ");" << endl
@@ -1756,11 +1868,15 @@
 
 void t_netstd_generator::generate_netstd_struct_equals(ostream& out, t_struct* tstruct)
 {
-    out << indent() << "public override bool Equals(object that)" << endl
+    out << indent() << "public override bool Equals(object" << nullable_suffix() << " that)" << endl
         << indent() << "{" << endl;
     indent_up();
-    out << indent() << "if (!(that is " << type_name(tstruct,false) << " other)) return false;" << endl
-        << indent() << "if (ReferenceEquals(this, other)) return true;" << endl;
+    if(use_net6_features) {
+        out << indent() << "if (that is not " << type_name(tstruct,false) << " other) return false;" << endl;
+    } else {
+        out << indent() << "if (!(that is " << type_name(tstruct,false) << " other)) return false;" << endl;
+    }
+    out << indent() << "if (ReferenceEquals(this, other)) return true;" << endl;
 
 
     const vector<t_field*>& fields = tstruct->get_members();
@@ -1838,7 +1954,7 @@
             out << "TCollections.GetHashCode(" << prop_name((*f_iter)) << ")";
         }
         else {
-            out << prop_name((*f_iter)) << ".GetHashCode()";
+            out << prop_name(*f_iter) << ".GetHashCode()";
         }
         out << ";" << endl;
 
@@ -1862,8 +1978,9 @@
     f_service.open(f_service_name.c_str());
 
     reset_indent();
-    f_service << autogen_comment() << netstd_type_usings() << netstd_thrift_usings() << endl;
+    f_service << autogen_comment() << netstd_type_usings() << netstd_thrift_usings() << endl << endl;
 
+    pragmas_and_directives(f_service);
     start_netstd_namespace(f_service);
 
     f_service << indent() << "public partial class " << normalize_name(service_name_) << endl
@@ -2106,7 +2223,8 @@
                 out << indent() << "if (" << tmpvar << ".__isset.success)" << endl
                     << indent() << "{" << endl;
                 indent_up();
-                out << indent() << "return " << tmpvar << ".Success;" << endl;
+                string nullable_value = nullable_value_access((*functions_iterator)->get_returntype());
+                out << indent() << "return " << tmpvar << ".Success" << nullable_value << ";" << endl;
                 indent_down();
                 out << indent() << "}" << endl;
             }
@@ -2118,7 +2236,7 @@
                 out << indent() << "if (" << tmpvar << ".__isset." << get_isset_name(normalize_name((*x_iter)->get_name())) << ")" << endl
                     << indent() << "{" << endl;
                 indent_up();
-                out << indent() << "throw " << tmpvar << "." << prop_name(*x_iter) << ";" << endl;
+                out << indent() << "throw " << tmpvar << "." << prop_name(*x_iter) << nullable_value_access((*x_iter)->get_type()) << ";" << endl;
                 indent_down();
                 out << indent() << "}" << endl;
             }
@@ -2162,9 +2280,9 @@
     indent_up();
 
     out << indent() << "private readonly IAsync _iAsync;" << endl
-        << indent() << "private readonly ILogger<AsyncProcessor> _logger;" << endl
+        << indent() << "private readonly ILogger<AsyncProcessor>" << nullable_suffix() << " _logger;" << endl
         << endl
-        << indent() << "public AsyncProcessor(IAsync iAsync, ILogger<AsyncProcessor> logger = default)";
+        << indent() << "public AsyncProcessor(IAsync iAsync, ILogger<AsyncProcessor>" << nullable_suffix() << " logger = default)";
 
     if (!extends.empty())
     {
@@ -2194,7 +2312,9 @@
 
     if (extends.empty())
     {
-        out << indent() << "protected Dictionary<string, ProcessFunction> processMap_ = new Dictionary<string, ProcessFunction>();" << endl;
+        out << indent() << "protected Dictionary<string, ProcessFunction> processMap_ = new"
+            << (use_net6_features ? "" : " Dictionary<string, ProcessFunction>")  // Simplify new expression (IDE0090)
+            << "();" << endl;
     }
 
     out << endl;
@@ -2229,7 +2349,7 @@
     indent_up();
     out << indent() << "var msg = await iprot.ReadMessageBeginAsync(" << CANCELLATION_TOKEN_NAME << ");" << endl
         << endl
-        << indent() << "processMap_.TryGetValue(msg.Name, out ProcessFunction fn);" << endl
+        << indent() << "processMap_.TryGetValue(msg.Name, out var fn);" << endl
         << endl
         << indent() << "if (fn == null)" << endl
         << indent() << "{" << endl;
@@ -2654,15 +2774,15 @@
 
     if (ttype->is_map())
     {
-        out << indent() << "TMap " << obj << " = await iprot.ReadMapBeginAsync(" << CANCELLATION_TOKEN_NAME << ");" << endl;
+        out << indent() << "var " << obj << " = await iprot.ReadMapBeginAsync(" << CANCELLATION_TOKEN_NAME << ");" << endl;
     }
     else if (ttype->is_set())
     {
-        out << indent() << "TSet " << obj << " = await iprot.ReadSetBeginAsync(" << CANCELLATION_TOKEN_NAME << ");" << endl;
+        out << indent() << "var " << obj << " = await iprot.ReadSetBeginAsync(" << CANCELLATION_TOKEN_NAME << ");" << endl;
     }
     else if (ttype->is_list())
     {
-        out << indent() << "TList " << obj << " = await iprot.ReadListBeginAsync(" << CANCELLATION_TOKEN_NAME << ");" << endl;
+        out << indent() << "var " << obj << " = await iprot.ReadListBeginAsync(" << CANCELLATION_TOKEN_NAME << ");" << endl;
     }
 
     out << indent() << prefix << " = new " << type_name(ttype) << "(" << obj << ".Count);" << endl;
@@ -2712,8 +2832,8 @@
     t_field fkey(tmap->get_key_type(), key);
     t_field fval(tmap->get_val_type(), val);
 
-    out << indent() << declare_field(&fkey) << endl;
-    out << indent() << declare_field(&fval) << endl;
+    out << indent() << declare_field(&fkey, false, false) << endl;
+    out << indent() << declare_field(&fval, false, false) << endl;
 
     generate_deserialize_field(out, &fkey);
     generate_deserialize_field(out, &fval);
@@ -2726,7 +2846,7 @@
     string elem = tmp("_elem");
     t_field felem(tset->get_elem_type(), elem);
 
-    out << indent() << declare_field(&felem) << endl;
+    out << indent() << declare_field(&felem, false, false) << endl;
 
     generate_deserialize_field(out, &felem);
 
@@ -2738,19 +2858,20 @@
     string elem = tmp("_elem");
     t_field felem(tlist->get_elem_type(), elem);
 
-    out << indent() << declare_field(&felem) << endl;
+    out << indent() << declare_field(&felem, false, false) << endl;
 
     generate_deserialize_field(out, &felem);
 
     out << indent() << prefix << ".Add(" << elem << ");" << endl;
 }
 
-void t_netstd_generator::generate_serialize_field(ostream& out, t_field* tfield, string prefix, bool is_propertyless)
+void t_netstd_generator::generate_serialize_field(ostream& out, t_field* tfield, string prefix, bool is_propertyless, bool allow_nullable)
 {
     t_type* type = tfield->get_type();
     type = resolve_typedef( type);
 
     string name = prefix + (is_propertyless ? "" : prop_name(tfield));
+    string nullable_name = name + (allow_nullable ? nullable_value_access(type) : "");
 
     if (type->is_void())
     {
@@ -2769,8 +2890,6 @@
     {
         out << indent() << "await oprot.";
 
-        string nullable_name = name;
-
         if (type->is_base_type())
         {
             t_base_type::t_base tbase = static_cast<t_base_type*>(type)->get_base();
@@ -2813,7 +2932,7 @@
         }
         else if (type->is_enum())
         {
-            out << "WriteI32Async((int)" << nullable_name << ", " << CANCELLATION_TOKEN_NAME << ");";
+            out << "WriteI32Async((int)" << name << ", " << CANCELLATION_TOKEN_NAME << ");";
         }
         out << endl;
     }
@@ -2831,9 +2950,6 @@
 
 void t_netstd_generator::generate_serialize_container(ostream& out, t_type* ttype, string prefix)
 {
-    out << indent() << "{" << endl;
-    indent_up();
-
     if (ttype->is_map())
     {
         out << indent() << "await oprot.WriteMapBeginAsync(new TMap(" << type_to_enum(static_cast<t_map*>(ttype)->get_key_type())
@@ -2901,29 +3017,26 @@
     {
         out << indent() << "await oprot.WriteListEndAsync(" << CANCELLATION_TOKEN_NAME << ");" << endl;
     }
-
-    indent_down();
-    out << indent() << "}" << endl;
 }
 
 void t_netstd_generator::generate_serialize_map_element(ostream& out, t_map* tmap, string iter, string map)
 {
     t_field kfield(tmap->get_key_type(), iter);
-    generate_serialize_field(out, &kfield, "");
+    generate_serialize_field(out, &kfield, "", false, false);
     t_field vfield(tmap->get_val_type(), map + "[" + iter + "]");
-    generate_serialize_field(out, &vfield, "");
+    generate_serialize_field(out, &vfield, "", false, false);
 }
 
 void t_netstd_generator::generate_serialize_set_element(ostream& out, t_set* tset, string iter)
 {
     t_field efield(tset->get_elem_type(), iter);
-    generate_serialize_field(out, &efield, "");
+    generate_serialize_field(out, &efield, "", false, false);
 }
 
 void t_netstd_generator::generate_serialize_list_element(ostream& out, t_list* tlist, string iter)
 {
     t_field efield(tlist->get_elem_type(), iter);
-    generate_serialize_field(out, &efield, "");
+    generate_serialize_field(out, &efield, "", false, false);
 }
 
 void t_netstd_generator::generate_property(ostream& out, t_field* tfield, bool isPublic, bool generateIsset)
@@ -2937,12 +3050,23 @@
     {
         out << indent() << "[DataMember(Order = 0)]" << endl;
     }
-    out << indent() << (isPublic ? "public " : "private ") << type_name(tfield->get_type()) << " " << prop_name(tfield);
+
+    out << indent()
+        << (isPublic ? "public " : "private ")
+        << type_name(tfield->get_type())
+        << nullable_field_suffix(tfield)
+        << " "
+        << prop_name(tfield)
+        ;
 
     bool is_required = field_is_required(tfield);
     if (is_required)
     {
-        out << " { get; set; }" << endl;
+        out << " { get; set; }";
+        if( use_net6_features && (!force_member_nullable(tfield))) {
+            out << initialize_field(tfield) << ";";
+        }
+        out << endl;
     }
     else
     {
@@ -3214,6 +3338,105 @@
   return get_mapped_member_name(fname);
 }
 
+bool t_netstd_generator::is_nullable_type(t_type* ttype) {
+  ttype = resolve_typedef(ttype);
+
+  if (ttype->is_enum()) {
+    return false;
+  }
+
+  if (ttype->is_base_type()) {
+    t_base_type::t_base tbase = static_cast<t_base_type*>(ttype)->get_base();
+    switch (tbase)
+    {
+    case t_base_type::TYPE_STRING:
+      return true;  // both binary and string
+    default:
+      return false;
+    }
+  }
+
+  return true;
+}
+
+
+string t_netstd_generator::nullable_suffix() {
+  if(use_net6_features) {
+    return "?";
+  } else {
+    return "";
+  }
+}
+
+
+string t_netstd_generator::nullable_field_suffix(t_field* tfield) {
+  if(field_is_required(tfield) && (!force_member_nullable(tfield)))
+    return "";
+  else
+    return nullable_field_suffix(tfield->get_type());
+}
+  
+
+string t_netstd_generator::nullable_field_suffix(t_type* ttype) {
+  if( ! use_net6_features) {
+    return "";
+  }
+
+  ttype = resolve_typedef(ttype);
+
+  if (ttype->is_enum()) {
+    return "";
+  }
+
+  if (ttype->is_base_type()) {
+    t_base_type::t_base tbase = static_cast<t_base_type*>(ttype)->get_base();
+    switch (tbase)
+    {
+    case t_base_type::TYPE_STRING:
+      return nullable_suffix();
+    default:
+      return "";
+    }
+  }
+
+  return nullable_suffix();
+}
+
+string t_netstd_generator::nullable_value_access(t_type* ttype) {
+  if( ! use_net6_features)
+    return "";
+
+  ttype = resolve_typedef(ttype);
+
+  // this code uses the null-forgiving operator and therefore assumes that the variable
+  // has been properly checked against an isset guard or null
+  if (ttype->is_base_type()) {
+    t_base_type::t_base tbase = static_cast<t_base_type*>(ttype)->get_base();
+    switch (tbase)
+    {
+    case t_base_type::TYPE_STRING:
+      return "!";
+    default:
+      return "";
+    }
+  }
+
+  if (ttype->is_container() || ttype->is_struct() || ttype->is_xception()) {
+    return "!";
+  }
+
+  return "";
+}
+
+bool t_netstd_generator::force_member_nullable(t_field* tfield) {
+  // IMPORTANT: 
+  // If tfield is a struct that contains a required field of the same type (directly or indirectly),
+  // auto-initializing such a member field would immediately produce an OOM, or at least unexpectedly 
+  // allocate potentially large amounts of memory -> ALWAYS leave containers and struct members nullable
+  t_type* ttype = resolve_typedef(tfield->get_type());
+  return ttype->is_struct() || ttype->is_container();
+}
+
 string t_netstd_generator::type_name(t_type* ttype, bool with_namespace)
 {
     ttype = resolve_typedef(ttype);
@@ -3232,7 +3455,7 @@
     if (ttype->is_set())
     {
         t_set* tset = static_cast<t_set*>(ttype);
-        return "THashSet<" + type_name(tset->get_elem_type()) + ">";
+		return "HashSet<" + type_name(tset->get_elem_type()) + ">";
     }
 
     if (ttype->is_list())
@@ -3266,8 +3489,7 @@
     case t_base_type::TYPE_VOID:
         return "void";
     case t_base_type::TYPE_STRING:
-        if (tbase->is_binary())
-        {
+        if (tbase->is_binary()) {
             return "byte[]";
         } else {
             return "string";
@@ -3289,10 +3511,14 @@
     }
 }
 
-string t_netstd_generator::get_deep_copy_method_call(t_type* ttype, bool& needs_typecast)
+string t_netstd_generator::get_deep_copy_method_call(t_type* ttype, bool is_not_null, bool& needs_typecast, string& suffix)
 {
     ttype = resolve_typedef(ttype);
 
+    // if is_not_null is set, then the surrounding code already explicitly tests against != null
+    string null_check("");
+
+    suffix = "";
     needs_typecast = false;
     if (ttype->is_base_type())
     {
@@ -3300,11 +3526,17 @@
         switch (tbase)
         {
         case t_base_type::TYPE_STRING:
-            if (ttype->is_binary())
-            {
-                return ".ToArray()";
+            if (ttype->is_binary()) {
+                suffix = nullable_suffix();
+                if( use_net6_features) {
+                    null_check = is_not_null ? "!" : " ?? Array.Empty<byte>()";
+                }
+                return ".ToArray()" + null_check;
             } else {
-                return "";  // simple assignment will do, strings are immutable in C#
+                if( use_net6_features) {
+                    null_check = is_not_null ? "!" : " ?? string.Empty";
+                }
+                return null_check;  // simple assignment will do, strings are immutable in C#
             }
             break;
         default:
@@ -3315,63 +3547,116 @@
     {
         return "";  // simple assignment will do
     }
+    else if (is_union_enabled() && ttype->is_struct() && static_cast<t_struct*>(ttype)->is_union())
+    {
+        needs_typecast = (! ttype->is_container());        
+        suffix = nullable_suffix();
+        if( use_net6_features) {
+            null_check = is_not_null ? "!" : " ?? new "+ttype->get_name() +".___undefined()";
+        }        
+        return "." + DEEP_COPY_METHOD_NAME + "()" + null_check;
+    }
     else
     {
-        needs_typecast = (! ttype->is_container());
-        return "." + DEEP_COPY_METHOD_NAME + "()";
+        needs_typecast = (! ttype->is_container());        
+        suffix = nullable_suffix();
+        if( use_net6_features) {
+            null_check = is_not_null ? "!" : " ?? new()";
+        }        
+        return "." + DEEP_COPY_METHOD_NAME + "()" + null_check;
     }
+    
+    throw "UNEXPECTED TYPE IN get_deep_copy_method_call: " + ttype->get_name();
 }
 
-string t_netstd_generator::declare_field(t_field* tfield, bool init, string prefix)
+string t_netstd_generator::declare_field(t_field* tfield, bool init, bool allow_nullable, string prefix)
 {
-    string result = type_name(tfield->get_type()) + " " + prefix + tfield->get_name();
+    string result = type_name(tfield->get_type())
+                  + (allow_nullable ? nullable_field_suffix(tfield) : "")
+                  + " "
+                  + prefix + tfield->get_name()
+                  ;
     if (init)
     {
-        t_type* ttype = tfield->get_type();
-        ttype = resolve_typedef(ttype);
-        if (ttype->is_base_type() && field_has_default(tfield))
+        result += initialize_field(tfield);
+    }
+
+    return result + ";";
+}
+
+string t_netstd_generator::initialize_field(t_field* tfield)
+{
+    t_type* ttype = tfield->get_type();
+    ttype = resolve_typedef(ttype);    
+    
+    if (ttype->is_base_type() && field_has_default(tfield))
+    {
+        std::ofstream dummy;
+        return " = " + render_const_value(dummy, tfield->get_name(), ttype, tfield->get_value());
+    }
+    else if (force_member_nullable(tfield))
+    {
+        return "";  // see force_member_nullable() why this is necessary
+    }
+    else if (ttype->is_base_type())
+    {
+        t_base_type::t_base tbase = static_cast<t_base_type*>(ttype)->get_base();
+        switch (tbase)
         {
-            std::ofstream dummy;
-            result += " = " + render_const_value(dummy, tfield->get_name(), ttype, tfield->get_value());
-        }
-        else if (ttype->is_base_type())
-        {
-            t_base_type::t_base tbase = static_cast<t_base_type*>(ttype)->get_base();
-            switch (tbase)
-            {
-            case t_base_type::TYPE_VOID:
-                throw "NO T_VOID CONSTRUCT";
-            case t_base_type::TYPE_STRING:
-                result += " = null";
-                break;
-            case t_base_type::TYPE_BOOL:
-                result += " = false";
-                break;
-            case t_base_type::TYPE_I8:
-            case t_base_type::TYPE_I16:
-            case t_base_type::TYPE_I32:
-            case t_base_type::TYPE_I64:
-                result += " = 0";
-                break;
-            case t_base_type::TYPE_DOUBLE:
-                result += " = (double)0";
-                break;
+        case t_base_type::TYPE_VOID:
+            throw "NO T_VOID CONSTRUCT";
+        case t_base_type::TYPE_STRING:
+            if(use_net6_features && field_is_required(tfield)) {
+                if (ttype->is_binary()) {
+                    return " = Array.Empty<byte>()";
+                } else {
+                    return " = string.Empty";
+                }
+            } else {
+                return " = null";
             }
-        }
-        else if (ttype->is_enum())
-        {
-            result += " = (" + type_name(ttype) + ")0";
-        }
-        else if (ttype->is_container())
-        {
-            result += " = new " + type_name(ttype) + "()";
-        }
-        else
-        {
-            result += " = new " + type_name(ttype) + "()";
+            break;
+        case t_base_type::TYPE_BOOL:
+            return " = false";
+            break;
+        case t_base_type::TYPE_I8:
+        case t_base_type::TYPE_I16:
+        case t_base_type::TYPE_I32:
+        case t_base_type::TYPE_I64:
+            return " = 0";
+            break;
+        case t_base_type::TYPE_DOUBLE:
+            return " = 0.0";
+            break;
         }
     }
-    return result + ";";
+    else if (ttype->is_enum())
+    {
+        return " = default";
+    }
+    else if (ttype->is_container())
+    {
+        if(use_net6_features) {
+            return " = new()";
+        } else {
+            return " = new " + type_name(ttype) + "()";
+        }
+    }
+    else if (ttype->is_struct())
+    {
+        t_struct* tstruct = static_cast<t_struct*>(ttype);        
+        if(use_net6_features) {
+            if(tstruct->is_union()) {
+                return " = new " + type_name(ttype) + ".___undefined()";
+            } else {
+                return " = new()";
+            }
+        } else {
+            return " = new " + type_name(ttype) + "()";
+        }
+    }
+    
+    throw "UNEXPECTED TYPE IN initialize_field: " + ttype->get_name();
 }
 
 string t_netstd_generator::function_signature(t_function* tfunction, string prefix)
@@ -3421,7 +3706,7 @@
         }
 
         if( with_types) {
-            result += type_name((*f_iter)->get_type()) + " ";
+            result += type_name((*f_iter)->get_type()) + nullable_field_suffix(*f_iter) + " ";
         }
 
         result += normalize_name((*f_iter)->get_name(),true);
@@ -3582,6 +3867,7 @@
     "    serial:          Add serialization support to generated classes.\n"
     "    union:           Use new union typing, which includes a static read function for union types.\n"
     "    pascal:          Generate Pascal Case property names according to Microsoft naming convention.\n"
-    "    no_deepcopy:     Suppress generation of DeepCopy() method.\n"
+    "    net6:            Enable features that require net6 and C# 8 or higher.\n"
+    "    no_deepcopy:     Suppress generation of " + DEEP_COPY_METHOD_NAME + "() method.\n"
     "    async_postfix:   Append \"Async\" to all service methods (maintains compatibility with existing code).\n"
 )
diff --git a/compiler/cpp/src/thrift/generate/t_netstd_generator.h b/compiler/cpp/src/thrift/generate/t_netstd_generator.h
index 31226f2..982cd26 100644
--- a/compiler/cpp/src/thrift/generate/t_netstd_generator.h
+++ b/compiler/cpp/src/thrift/generate/t_netstd_generator.h
@@ -69,16 +69,16 @@
   map<string, int> get_keywords_list() const;
 
   // overrides
-  void init_generator();
-  void close_generator();
-  void generate_consts(vector<t_const*> consts);
+  void init_generator() override;
+  void close_generator() override;
+  void generate_consts(vector<t_const*> consts) override;
   void generate_consts(ostream& out, vector<t_const*> consts);
-  void generate_typedef(t_typedef* ttypedef);
-  void generate_enum(t_enum* tenum);
+  void generate_typedef(t_typedef* ttypedef) override;
+  void generate_enum(t_enum* tenum) override;
   void generate_enum(ostream& out, t_enum* tenum);
-  void generate_struct(t_struct* tstruct);
-  void generate_xception(t_struct* txception);
-  void generate_service(t_service* tservice);
+  void generate_struct(t_struct* tstruct) override;
+  void generate_xception(t_struct* txception) override;
+  void generate_service(t_service* tservice) override;
 
   // additional files
   void generate_extensions_file();
@@ -116,7 +116,7 @@
   void generate_deserialize_set_element(ostream& out, t_set* tset, string prefix = "");
   void generate_deserialize_map_element(ostream& out, t_map* tmap, string prefix = "");
   void generate_deserialize_list_element(ostream& out, t_list* list, string prefix = "");
-  void generate_serialize_field(ostream& out, t_field* tfield, string prefix = "", bool is_propertyless = false);
+  void generate_serialize_field(ostream& out, t_field* tfield, string prefix = "", bool is_propertyless = false, bool allow_nullable = true);
   void generate_serialize_struct(ostream& out, t_struct* tstruct, string prefix = "");
   void generate_serialize_container(ostream& out, t_type* ttype, string prefix = "");
   void generate_serialize_map_element(ostream& out, t_map* tmap, string iter, string map);
@@ -139,7 +139,7 @@
 
   string type_name(t_type* ttype, bool with_namespace = true);
   string base_type_name(t_base_type* tbase);
-  string declare_field(t_field* tfield, bool init = false, string prefix = "");
+  string declare_field(t_field* tfield, bool init = false, bool allow_nullable = true, string prefix = "");
   string function_signature_async(t_function* tfunction, string prefix = "", int mode = MODE_FULL_DECL);
   string function_signature(t_function* tfunction, string prefix = "");
   string argument_list(t_struct* tstruct, bool with_types = true);
@@ -148,19 +148,23 @@
   string func_name(t_function* tfunc, bool suppress_mapping = false);
   string func_name(std::string fname, bool suppress_mapping = false);
   string convert_to_pascal_case(const string& str);
-  string get_enum_class_name(t_type* type);
+  string get_enum_class_name(t_type* type) override;
 
 protected:
   std::string autogen_comment() override {
-    return std::string("/**\n") 
-                      + " * <auto-generated>\n"
-                      + " * " + autogen_summary() + "\n" 
-                      + " * DO NOT EDIT UNLESS YOU ARE SURE THAT YOU KNOW WHAT YOU ARE DOING\n"
-                      + " * </auto-generated>\n"
-                      " */\n"
-                      ;
+    string comment = "/**\n";
+    if( ! use_net6_features) {
+        comment += " * <auto-generated>\n";
+    }
+    comment += " * " + autogen_summary() + "\n";
+    comment += " * DO NOT EDIT UNLESS YOU ARE SURE THAT YOU KNOW WHAT YOU ARE DOING\n";
+    if( ! use_net6_features) {
+        comment += " * </auto-generated>\n";
+    }
+    comment += " */\n";
+    return comment;
   }
-
+  
 
 private:
   string namespace_name_;
@@ -172,6 +176,7 @@
   bool wcf_;
   bool use_pascal_case_properties;
   bool suppress_deepcopy;
+  bool use_net6_features;
   bool add_async_postfix;
 
   string wcf_namespace_;
@@ -191,11 +196,20 @@
   void cleanup_member_name_mapping(void* scope);
   string get_mapped_member_name(string oldname);
   string get_isset_name(const string& str);
-  string get_deep_copy_method_call(t_type* ttype, bool& needs_typecast);
+  string get_deep_copy_method_call(t_type* ttype, bool is_not_null, bool& needs_typecast, string& suffix);
   void collect_extensions_types(t_struct* tstruct);
   void collect_extensions_types(t_type* ttype);
   void generate_extensions(ostream& out, map<string, t_type*> types);
   void reset_indent();
   void generate_null_check_begin(ostream& out, t_field* tfield);
   void generate_null_check_end(ostream& out, t_field* tfield);
+  string initialize_field(t_field* tfield);
+
+  void pragmas_and_directives(ostream& out);
+  bool is_nullable_type(t_type* ttype);
+  bool force_member_nullable(t_field* tfield);  // see there
+  string nullable_suffix();                     // unconditionally
+  string nullable_field_suffix(t_field* tfield);  // depends on field type
+  string nullable_field_suffix(t_type* ttype);  // depends on field type
+  string nullable_value_access(t_type* ttype);  // depends on field type
 };
diff --git a/compiler/cpp/src/thrift/parse/t_field.h b/compiler/cpp/src/thrift/parse/t_field.h
index 4be8770..f0a607d 100644
--- a/compiler/cpp/src/thrift/parse/t_field.h
+++ b/compiler/cpp/src/thrift/parse/t_field.h
@@ -41,6 +41,7 @@
     : type_(type),
       name_(name),
       key_(0),
+	  req_(T_OPT_IN_REQ_OUT),
       value_(nullptr),
       xsd_optional_(false),
       xsd_nillable_(false),
diff --git a/compiler/cpp/src/thrift/version.h b/compiler/cpp/src/thrift/version.h
index bce719a..2a4b925 100644
--- a/compiler/cpp/src/thrift/version.h
+++ b/compiler/cpp/src/thrift/version.h
@@ -24,6 +24,6 @@
 #pragma once
 #endif // _MSC_VER
 
-#define THRIFT_VERSION "0.16.0"
+#define THRIFT_VERSION "0.17.0"
 
 #endif // _THRIFT_VERSION_H_
diff --git a/configure.ac b/configure.ac
index 32c2471..1ab550a 100755
--- a/configure.ac
+++ b/configure.ac
@@ -20,7 +20,7 @@
 AC_PREREQ(2.65)
 AC_CONFIG_MACRO_DIR([./aclocal])
 
-AC_INIT([thrift], [0.16.0])
+AC_INIT([thrift], [0.17.0])
 
 AC_CONFIG_AUX_DIR([.])
 
diff --git a/contrib/Rebus/Properties/AssemblyInfo.cs b/contrib/Rebus/Properties/AssemblyInfo.cs
index 97c89d1..cc3204a 100644
--- a/contrib/Rebus/Properties/AssemblyInfo.cs
+++ b/contrib/Rebus/Properties/AssemblyInfo.cs
@@ -34,5 +34,5 @@
 
 [assembly: Guid("0af10984-40d3-453d-b1e5-421529e8c7e2")]
 
-[assembly: AssemblyVersion("0.16.0.0")]
-[assembly: AssemblyFileVersion("0.16.0.0")]
+[assembly: AssemblyVersion("0.17.0.0")]
+[assembly: AssemblyFileVersion("0.17.0.0")]
diff --git a/contrib/thrift-maven-plugin/pom.xml b/contrib/thrift-maven-plugin/pom.xml
index 1290895..da8491d 100644
--- a/contrib/thrift-maven-plugin/pom.xml
+++ b/contrib/thrift-maven-plugin/pom.xml
@@ -32,7 +32,7 @@
   <artifactId>thrift-maven-plugin</artifactId>
   <packaging>maven-plugin</packaging>
   <name>thrift-maven-plugin</name>
-  <version>0.16.0</version>
+  <version>0.17.0</version>
 
   <properties>
     <maven.compiler.source>1.8</maven.compiler.source>
diff --git a/contrib/thrift.spec b/contrib/thrift.spec
index feb95a1..92af91e 100644
--- a/contrib/thrift.spec
+++ b/contrib/thrift.spec
@@ -28,7 +28,7 @@
 License:        Apache License v2.0
 Group:          Development
 Summary:        RPC and serialization framework
-Version:        0.16.0
+Version:        0.17.0
 Release:        0
 URL:            http://thrift.apache.org
 Packager:       Thrift Developers <dev@thrift.apache.org>
diff --git a/contrib/zeromq/csharp/AssemblyInfo.cs b/contrib/zeromq/csharp/AssemblyInfo.cs
index dc59f23..8f46c92 100644
--- a/contrib/zeromq/csharp/AssemblyInfo.cs
+++ b/contrib/zeromq/csharp/AssemblyInfo.cs
@@ -36,7 +36,7 @@
 // The form "{Major}.{Minor}.*" will automatically update the build and revision,
 // and "{Major}.{Minor}.{Build}.*" will update just the revision.
 
-[assembly: AssemblyVersion("0.16.0.0")]
+[assembly: AssemblyVersion("0.17.0.0")]
 
 // The following attributes are used to specify the signing key for the assembly,
 // if desired. See the Mono documentation for more information about signing.
diff --git a/debian/changelog b/debian/changelog
index 52f87e3..c570028 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+thrift (0.16.0) stable; urgency=low
+
+  * update to 0.16.0
+
+ -- Apache Thrift Developers <dev@thrift.apache.org>  Wed, 20 Jan 2022 21:00:00 +0100
+
 thrift (0.15.0) stable; urgency=low
 
   * update to 0.15.0
diff --git a/doap.rdf b/doap.rdf
index eabb232..36c54e6 100755
--- a/doap.rdf
+++ b/doap.rdf
@@ -57,6 +57,11 @@
     <release rdf:parseType="Collection">
       <Version>
         <name>Apache Thrift</name>
+        <created>2022-01-20</created>
+        <revision>0.16.0</revision>
+      </Version>
+      <Version>
+        <name>Apache Thrift</name>
         <created>2021-08-03</created>
         <revision>0.15.0</revision>
       </Version>
diff --git a/doc/specs/idl.md b/doc/specs/idl.md
index 019c7f6..1c6a94a 100644
--- a/doc/specs/idl.md
+++ b/doc/specs/idl.md
@@ -1,6 +1,6 @@
 ## Thrift interface description language
 
-For Thrift version 0.16.0.
+For Thrift version 0.17.0.
 
 The Thrift interface definition language (IDL) allows for the definition of [Thrift Types](/docs/types). A Thrift IDL file is processed by the Thrift code generator to produce code for the various target languages to support the defined structs and services in the IDL file.
 
diff --git a/lib/cpp/src/thrift/protocol/TProtocol.h b/lib/cpp/src/thrift/protocol/TProtocol.h
index 867ceb0..b691c41 100644
--- a/lib/cpp/src/thrift/protocol/TProtocol.h
+++ b/lib/cpp/src/thrift/protocol/TProtocol.h
@@ -22,7 +22,7 @@
 
 #ifdef _WIN32
 // Need to come before any Windows.h includes
-#include <Winsock2.h>
+#include <winsock2.h>
 #endif
 
 #include <thrift/transport/TTransport.h>
diff --git a/lib/cpp/src/thrift/windows/GetTimeOfDay.cpp b/lib/cpp/src/thrift/windows/GetTimeOfDay.cpp
index ac24124..d369605 100644
--- a/lib/cpp/src/thrift/windows/GetTimeOfDay.cpp
+++ b/lib/cpp/src/thrift/windows/GetTimeOfDay.cpp
@@ -38,7 +38,7 @@
 }
 #else
 #define WIN32_LEAN_AND_MEAN
-#include <Winsock2.h>
+#include <winsock2.h>
 #include <cstdint>
 #include <sstream>
 #include <thrift/transport/TTransportException.h>
diff --git a/lib/cpp/src/thrift/windows/SocketPair.h b/lib/cpp/src/thrift/windows/SocketPair.h
index 86bf431..74b65df 100644
--- a/lib/cpp/src/thrift/windows/SocketPair.h
+++ b/lib/cpp/src/thrift/windows/SocketPair.h
@@ -29,7 +29,7 @@
 #endif
 
 // Win32
-#include <Winsock2.h>
+#include <winsock2.h>
 #include <thrift/thrift-config.h>
 
 int thrift_socketpair(int d, int type, int protocol, THRIFT_SOCKET sv[2]);
diff --git a/lib/cpp/src/thrift/windows/Sync.h b/lib/cpp/src/thrift/windows/Sync.h
index f5b8a05..a5b2ac5 100644
--- a/lib/cpp/src/thrift/windows/Sync.h
+++ b/lib/cpp/src/thrift/windows/Sync.h
@@ -29,11 +29,23 @@
 
 // Including Windows.h can conflict with Winsock2 usage, and also
 // adds problematic macros like min() and max(). Try to work around:
+#ifndef NOMINMAX
 #define NOMINMAX
+#define _THRIFT_UNDEF_NOMINMAX
+#endif
+#ifndef WIN32_LEAN_AND_MEAN
 #define WIN32_LEAN_AND_MEAN
+#define _THRIFT_UNDEF_WIN32_LEAN_AND_MEAN
+#endif
 #include <Windows.h>
+#ifdef _THRIFT_UNDEF_NOMINMAX
 #undef NOMINMAX
+#undef _THRIFT_UNDEF_NOMINMAX
+#endif
+#ifdef _THRIFT_UNDEF_WIN32_LEAN_AND_MEAN
 #undef WIN32_LEAN_AND_MEAN
+#undef _THRIFT_UNDEF_WIN32_LEAN_AND_MEAN
+#endif
 
 /*
   Lightweight synchronization objects that only make sense on Windows.  For cross-platform
diff --git a/lib/cpp/src/thrift/windows/WinFcntl.h b/lib/cpp/src/thrift/windows/WinFcntl.h
index 4816fc5..39e5efd 100644
--- a/lib/cpp/src/thrift/windows/WinFcntl.h
+++ b/lib/cpp/src/thrift/windows/WinFcntl.h
@@ -33,7 +33,7 @@
 #endif
 
 // Win32
-#include <Winsock2.h>
+#include <winsock2.h>
 #include <thrift/transport/PlatformSocket.h>
 
 extern "C" {
diff --git a/lib/cpp/src/thrift/windows/config.h b/lib/cpp/src/thrift/windows/config.h
index ce10c55..19296d6 100644
--- a/lib/cpp/src/thrift/windows/config.h
+++ b/lib/cpp/src/thrift/windows/config.h
@@ -57,7 +57,7 @@
 #include <thrift/windows/SocketPair.h>
 
 // windows
-#include <Winsock2.h>
+#include <winsock2.h>
 #include <ws2tcpip.h>
 
 #ifndef __MINGW32__
diff --git a/lib/cpp/test/OpenSSLManualInitTest.cpp b/lib/cpp/test/OpenSSLManualInitTest.cpp
index 935a205..bf6c153 100644
--- a/lib/cpp/test/OpenSSLManualInitTest.cpp
+++ b/lib/cpp/test/OpenSSLManualInitTest.cpp
@@ -21,7 +21,7 @@
 // which will cause the test to fail
 #define MANUAL_OPENSSL_INIT 1
 #ifdef _WIN32
-#include <WinSock2.h>
+#include <winsock2.h>
 #endif
 
 #include <boost/test/unit_test.hpp>
diff --git a/lib/d/src/thrift/base.d b/lib/d/src/thrift/base.d
index 471a253..56a4f60 100644
--- a/lib/d/src/thrift/base.d
+++ b/lib/d/src/thrift/base.d
@@ -50,7 +50,7 @@
 /// The Thrift version string, used for informative purposes.
 // Note: This is currently hardcoded, but will likely be filled in by the build
 // system in future versions.
-enum VERSION = "0.16.0";
+enum VERSION = "0.17.0";
 
 /**
  * Functions used for logging inside Thrift.
diff --git a/lib/dart/pubspec.yaml b/lib/dart/pubspec.yaml
index 8dbb367..a2f4b90 100644
--- a/lib/dart/pubspec.yaml
+++ b/lib/dart/pubspec.yaml
@@ -16,7 +16,7 @@
 # under the License.
 
 name: thrift
-version: 0.16.0
+version: 0.17.0
 description: >
   A Dart library for Apache Thrift
 author: Apache Thrift Developers <dev@thrift.apache.org>
diff --git a/lib/delphi/src/Thrift.pas b/lib/delphi/src/Thrift.pas
index bf9ac05..f8841f3 100644
--- a/lib/delphi/src/Thrift.pas
+++ b/lib/delphi/src/Thrift.pas
@@ -28,7 +28,7 @@
   Thrift.Protocol;
 
 const
-  Version = '0.16.0';
+  Version = '0.17.0';
 
 type
   TException = Thrift.Exception.TException; // compatibility alias
diff --git a/lib/erl/src/thrift.app.src b/lib/erl/src/thrift.app.src
index 0ce69b9..9c30c8a 100644
--- a/lib/erl/src/thrift.app.src
+++ b/lib/erl/src/thrift.app.src
@@ -22,7 +22,7 @@
   {description, "Thrift bindings"},
 
   % The version of the applicaton
-  {vsn, "0.16.0"},
+  {vsn, "0.17.0"},
 
   % All modules used by the application.
   {modules, [
diff --git a/lib/haxe/haxelib.json b/lib/haxe/haxelib.json
index 2d73ad8..5448e5f 100644
--- a/lib/haxe/haxelib.json
+++ b/lib/haxe/haxelib.json
@@ -10,7 +10,7 @@
 		"framework"
 	],
 	"description": "Haxe bindings for the Apache Thrift RPC and serialization framework",
-	"version": "0.16.0",
+	"version": "0.17.0",
 	"releasenote": "Licensed under Apache License, Version 2.0. The Apache Thrift compiler needs to be installed separately.",
 	"contributors": ["ApacheThrift"],
 	"dependencies": { 
diff --git a/lib/java/gradle.properties b/lib/java/gradle.properties
index fbb194d..8d4f0e4 100644
--- a/lib/java/gradle.properties
+++ b/lib/java/gradle.properties
@@ -1,7 +1,7 @@
 # This file is shared currently between this Gradle build and the
 # Ant builds for fd303 and JavaScript. Keep the dotted notation for
 # the properties to minimize the changes in the dependencies.
-thrift.version=0.16.0
+thrift.version=0.17.0
 thrift.groupid=org.apache.thrift
 release=false
 
diff --git a/lib/js/package-lock.json b/lib/js/package-lock.json
index b6633ac..8e764e3 100644
--- a/lib/js/package-lock.json
+++ b/lib/js/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "thrift",
-  "version": "0.16.0",
+  "version": "0.17.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/lib/js/package.json b/lib/js/package.json
index dfed941..ff57bf7 100644
--- a/lib/js/package.json
+++ b/lib/js/package.json
@@ -1,6 +1,6 @@
 {
   "name": "thrift",
-  "version": "0.16.0",
+  "version": "0.17.0",
   "description": "Thrift is a software framework for scalable cross-language services development.",
   "main": "./src/thrift",
   "author": {
diff --git a/lib/js/src/thrift.js b/lib/js/src/thrift.js
index 9933d60..17eb302 100644
--- a/lib/js/src/thrift.js
+++ b/lib/js/src/thrift.js
@@ -46,7 +46,7 @@
      * @const {string} Version
      * @memberof Thrift
      */
-    Version: '0.16.0',
+    Version: '0.17.0',
 
     /**
      * Thrift IDL type string to Id mapping.
diff --git a/lib/lua/Thrift.lua b/lib/lua/Thrift.lua
index 32c442b..252cded 100644
--- a/lib/lua/Thrift.lua
+++ b/lib/lua/Thrift.lua
@@ -48,7 +48,7 @@
   return count
 end
 
-version = '0.16.0'
+version = '0.17.0'
 
 TType = {
   STOP   = 0,
diff --git a/lib/netstd/Tests/Thrift.IntegrationTests/Thrift.IntegrationTests.csproj b/lib/netstd/Tests/Thrift.IntegrationTests/Thrift.IntegrationTests.csproj
index 56123dd..8c1b6a9 100644
--- a/lib/netstd/Tests/Thrift.IntegrationTests/Thrift.IntegrationTests.csproj
+++ b/lib/netstd/Tests/Thrift.IntegrationTests/Thrift.IntegrationTests.csproj
@@ -22,7 +22,7 @@
     <TargetFramework>net6.0</TargetFramework>
     <AssemblyName>Thrift.IntegrationTests</AssemblyName>
     <PackageId>Thrift.IntegrationTests</PackageId>
-    <Version>0.16.0.0</Version>
+    <Version>0.17.0.0</Version>
     <OutputType>Exe</OutputType>
     <GenerateAssemblyTitleAttribute>false</GenerateAssemblyTitleAttribute>
     <GenerateAssemblyDescriptionAttribute>false</GenerateAssemblyDescriptionAttribute>
diff --git a/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Impl/Thrift5253/MyService.cs b/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Impl/Thrift5253/MyService.cs
index 660b2b7..f423376 100644
--- a/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Impl/Thrift5253/MyService.cs
+++ b/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Impl/Thrift5253/MyService.cs
@@ -26,30 +26,30 @@
 {
     class MyServiceImpl : MyService.IAsync
     {
-        public Task<AsyncProcessor> AsyncProcessor_(AsyncProcessor input, CancellationToken cancellationToken = default)
+        public Task<AsyncProcessor> AsyncProcessor_(AsyncProcessor? input, CancellationToken cancellationToken = default)
         {
-            return Task.FromResult(new AsyncProcessor() { Foo = input.Foo });
+            return Task.FromResult(new AsyncProcessor() { Foo = input?.Foo ?? 0 });
         }
 
-        public Task<BrokenResult> Broken(BrokenArgs input, CancellationToken cancellationToken = default)
+        public Task<BrokenResult> Broken(BrokenArgs? input, CancellationToken cancellationToken = default)
         {
-            return Task.FromResult(new BrokenResult() { Foo = input.Foo });
+            return Task.FromResult(new BrokenResult() { Foo = input?.Foo ?? 0 });
         }
 
-        public Task<Client> Client_(Client input, CancellationToken cancellationToken = default)
+        public Task<Client> Client_(Client? input, CancellationToken cancellationToken = default)
         {
             _ = cancellationToken;
-            return Task.FromResult(new Client() { Foo = input.Foo });
+            return Task.FromResult(new Client() { Foo = input?.Foo ?? 0 });
         }
 
-        public Task<IAsync> IAsync_(IAsync input, CancellationToken cancellationToken = default)
+        public Task<IAsync> IAsync_(IAsync? input, CancellationToken cancellationToken = default)
         {
-            return Task.FromResult(new IAsync() { Foo = input.Foo });
+            return Task.FromResult(new IAsync() { Foo = input?.Foo ?? 0 });
         }
 
-        public Task<InternalStructs> InternalStructs_(InternalStructs input, CancellationToken cancellationToken = default)
+        public Task<InternalStructs> InternalStructs_(InternalStructs? input, CancellationToken cancellationToken = default)
         {
-            return Task.FromResult(new InternalStructs() { Foo = input.Foo });
+            return Task.FromResult(new InternalStructs() { Foo = input?.Foo ?? 0 });
         }
 
         public Task TestAsync(CancellationToken cancellationToken = default)
@@ -62,9 +62,9 @@
             return Task.CompletedTask;
         }
 
-        public Task<WorksRslt> Works(WorksArrrgs input, CancellationToken cancellationToken = default)
+        public Task<WorksRslt> Works(WorksArrrgs? input, CancellationToken cancellationToken = default)
         {
-            return Task.FromResult(new WorksRslt() { Foo = input.Foo });
+            return Task.FromResult(new WorksRslt() { Foo = input?.Foo ?? 0 });
         }
     }
 }
diff --git a/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Thrift.PublicInterfaces.Compile.Tests.csproj b/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Thrift.PublicInterfaces.Compile.Tests.csproj
index 0d2770d..42a139c 100644
--- a/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Thrift.PublicInterfaces.Compile.Tests.csproj
+++ b/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Thrift.PublicInterfaces.Compile.Tests.csproj
@@ -19,7 +19,7 @@
   -->
 
   <PropertyGroup>
-    <ThriftVersion>0.16.0</ThriftVersion>
+    <ThriftVersion>0.17.0</ThriftVersion>
     <ThriftVersionOutput>Thrift version $(ThriftVersion)</ThriftVersionOutput>
     <TargetFramework>net6.0</TargetFramework>
     <Version>$(ThriftVersion).0</Version>
@@ -68,14 +68,14 @@
     <Error Condition="$('$(ThriftBinaryVersion)'::StartsWith('$(ThriftVersionOutput)')) == true" Text="Thrift version returned: '$(ThriftBinaryVersion)' is not equal to the projects version '$(ThriftVersionOutput)'." />
     <Message Importance="high" Text="Generating tests with thrift binary: '$(PathToThrift)'" />
     <!-- Generate the thrift test files -->
-    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial -r ./CassandraTest.thrift" />
-    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial -r ./optional_required_default.thrift" />
-    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial -r ./name_conflicts.thrift" />
-    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial -r ./../../../../test/ThriftTest.thrift" />
-    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial -r ./../../../../contrib/fb303/if/fb303.thrift" />
-    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial -r ./Thrift5253.thrift" />
-    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial -r ./Thrift5320.thrift" />
-    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial -r ./Thrift5382.thrift" />
+    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial,net6 -r ./CassandraTest.thrift" />
+    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial,net6 -r ./optional_required_default.thrift" />
+    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial,net6 -r ./name_conflicts.thrift" />
+    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial,net6 -r ./../../../../test/ThriftTest.thrift" />
+    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial,net6 -r ./../../../../contrib/fb303/if/fb303.thrift" />
+    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial,net6 -r ./Thrift5253.thrift" />
+    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial,net6 -r ./Thrift5320.thrift" />
+    <Exec Command="$(PathToThrift) -gen netstd:wcf,union,serial,net6 -r ./Thrift5382.thrift" />
   </Target>
 
 </Project>
diff --git a/lib/netstd/Tests/Thrift.Tests/Collections/TCollectionsTests.cs b/lib/netstd/Tests/Thrift.Tests/Collections/TCollectionsTests.cs
index 778d24c..49108d1 100644
--- a/lib/netstd/Tests/Thrift.Tests/Collections/TCollectionsTests.cs
+++ b/lib/netstd/Tests/Thrift.Tests/Collections/TCollectionsTests.cs
@@ -83,8 +83,8 @@
         [TestMethod]
         public void TCollection_Set_Equals_Primitive_Test()
         {
-            var collection1 = new THashSet<int> {1,2,3};
-            var collection2 = new THashSet<int> {1,2,3};
+            var collection1 = new HashSet<int> {1,2,3};
+            var collection2 = new HashSet<int> {1,2,3};
             Assert.IsTrue(TCollections.Equals(collection1, collection2));
             Assert.IsTrue(collection1.SequenceEqual(collection2));
         }
@@ -92,8 +92,8 @@
         [TestMethod]
         public void TCollection_Set_Equals_Primitive_Different_Test()
         {
-            var collection1 = new THashSet<int> { 1, 2, 3 };
-            var collection2 = new THashSet<int> { 1, 2 };
+            var collection1 = new HashSet<int> { 1, 2, 3 };
+            var collection2 = new HashSet<int> { 1, 2 };
             Assert.IsFalse(TCollections.Equals(collection1, collection2));
             Assert.IsFalse(collection1.SequenceEqual(collection2));
 
@@ -105,8 +105,8 @@
         [TestMethod]
         public void TCollection_Set_Equals_Objects_Test()
         {
-            var collection1 = new THashSet<ExampleClass> { new ExampleClass { X = 1 }, new ExampleClass { X = 2 } };
-            var collection2 = new THashSet<ExampleClass> { new ExampleClass { X = 1 }, new ExampleClass { X = 2 } };
+            var collection1 = new HashSet<ExampleClass> { new ExampleClass { X = 1 }, new ExampleClass { X = 2 } };
+            var collection2 = new HashSet<ExampleClass> { new ExampleClass { X = 1 }, new ExampleClass { X = 2 } };
             Assert.IsTrue(TCollections.Equals(collection1, collection2));
             Assert.IsTrue(collection1.SequenceEqual(collection2));
         }
@@ -114,8 +114,8 @@
         [TestMethod]
         public void TCollection_Set_Set_Equals_Objects_Test()
         {
-            var collection1 = new THashSet<THashSet<ExampleClass>> { new THashSet<ExampleClass> { new ExampleClass { X = 1 }, new ExampleClass { X = 2 } } };
-            var collection2 = new THashSet<THashSet<ExampleClass>> { new THashSet<ExampleClass> { new ExampleClass { X = 1 }, new ExampleClass { X = 2 } } };
+            var collection1 = new HashSet<HashSet<ExampleClass>> { new HashSet<ExampleClass> { new ExampleClass { X = 1 }, new ExampleClass { X = 2 } } };
+            var collection2 = new HashSet<HashSet<ExampleClass>> { new HashSet<ExampleClass> { new ExampleClass { X = 1 }, new ExampleClass { X = 2 } } };
             Assert.IsTrue(TCollections.Equals(collection1, collection2));
             Assert.IsFalse(collection1.SequenceEqual(collection2));  // SequenceEqual() calls Equals() of the inner list instead of SequenceEqual()
         }
@@ -123,7 +123,7 @@
         [TestMethod]
         public void TCollection_Set_Equals_OneAndTheSameObject_Test()
         {
-            var collection1 = new THashSet<ExampleClass> { new ExampleClass { X = 1 }, new ExampleClass { X = 2 } };
+            var collection1 = new HashSet<ExampleClass> { new ExampleClass { X = 1 }, new ExampleClass { X = 2 } };
             var collection2 = collection1;      // references to one and the same collection
             Assert.IsTrue(TCollections.Equals(collection1, collection2));
             Assert.IsTrue(collection1.SequenceEqual(collection2));
diff --git a/lib/netstd/Tests/Thrift.Tests/Collections/THashSetTests.cs b/lib/netstd/Tests/Thrift.Tests/Collections/THashSetTests.cs
index 8de573e..73921ea 100644
--- a/lib/netstd/Tests/Thrift.Tests/Collections/THashSetTests.cs
+++ b/lib/netstd/Tests/Thrift.Tests/Collections/THashSetTests.cs
@@ -1,4 +1,4 @@
-﻿// Licensed to the Apache Software Foundation(ASF) under one
+// Licensed to the Apache Software Foundation(ASF) under one
 // or more contributor license agreements.See the NOTICE file
 // distributed with this work for additional information
 // regarding copyright ownership.The ASF licenses this file
@@ -22,6 +22,8 @@
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Thrift.Collections;
 
+#pragma warning disable IDE0063  // simplify using 
+
 namespace Thrift.Tests.Collections
 {
     // ReSharper disable once InconsistentNaming
@@ -33,7 +35,7 @@
         {
             const int value = 1;
 
-            var hashSet = new THashSet<int> {value};
+            var hashSet = new HashSet<int> {value};
             
             Assert.IsTrue(hashSet.Contains(value));
 
diff --git a/lib/netstd/Tests/Thrift.Tests/DataModel/DeepCopy.cs b/lib/netstd/Tests/Thrift.Tests/DataModel/DeepCopy.cs
index 84fcab8..afffed5 100644
--- a/lib/netstd/Tests/Thrift.Tests/DataModel/DeepCopy.cs
+++ b/lib/netstd/Tests/Thrift.Tests/DataModel/DeepCopy.cs
@@ -24,8 +24,6 @@
 using OptReqDefTest;
 using Thrift.Collections;
 
-#nullable disable  // this is just test code, we leave it at that
-
 namespace Thrift.Tests.DataModel
 {
     // ReSharper disable once InconsistentNaming
@@ -51,7 +49,7 @@
             VerifyIdenticalContent(first, InitializeInstance(new RaceDetails()));
         }
 
-        private RaceDetails MakeNestedRaceDetails(int nesting)
+        private RaceDetails? MakeNestedRaceDetails(int nesting)
         {
             if (++nesting > 1)
                 return null;
@@ -61,7 +59,7 @@
             return instance;
         }
 
-        private jack MakeNestedUnion(int nesting)
+        private jack? MakeNestedUnion(int nesting)
         {
             if (++nesting > 1)
                 return null;
@@ -88,11 +86,11 @@
             instance.Req_one = default;
             instance.Req_two = default;
             instance.Req_three = default;
-            instance.Req_four = default;
-            instance.Req_five = default;
+            Assert.IsNotNull(instance.Req_four);
+            Assert.IsNotNull(instance.Req_five);
             instance.Req_six = default; 
             instance.Req_seven = default;;
-            instance.Req_eight = default; 
+            instance.Req_eight = default;
 
             // leave non-required fields unset again
             Assert.IsFalse(instance.__isset.def_one);
@@ -119,15 +117,15 @@
             Assert.AreEqual(instance.Req_two_with_value, 2.22);
             Assert.AreEqual(instance.Req_three_with_value, 3);
             Assert.AreEqual(instance.Req_four_with_value, "four");
-            Assert.AreEqual("five", Encoding.UTF8.GetString(instance.Req_five_with_value));
+            Assert.AreEqual("five", Encoding.UTF8.GetString(instance.Req_five_with_value!));
 
-            Assert.IsTrue(instance.Req_six_with_value.Count == 1);
+            Assert.IsTrue(instance.Req_six_with_value!.Count == 1);
             Assert.AreEqual(instance.Req_six_with_value[0], 6 );
 
-            Assert.IsTrue(instance.Req_seven_with_value.Count == 1);
+            Assert.IsTrue(instance.Req_seven_with_value!.Count == 1);
             Assert.IsTrue(instance.Req_seven_with_value.Contains(7));
 
-            Assert.IsTrue(instance.Req_eight_with_value.Count == 1);
+            Assert.IsTrue(instance.Req_eight_with_value!.Count == 1);
             Assert.IsTrue(instance.Req_eight_with_value[8] == 8);
 
             Assert.IsTrue(instance.__isset.def_one_with_value);
@@ -144,12 +142,16 @@
             if (nesting < 2)
             {
                 instance.Far_list = new List<Distance>() { Distance.foo, Distance.bar, Distance.baz };
-                instance.Far_set = new THashSet<Distance>() { Distance.foo, Distance.bar, Distance.baz };
+                instance.Far_set = new HashSet<Distance>() { Distance.foo, Distance.bar, Distance.baz };
                 instance.Far_map = new Dictionary<Distance, Distance>() { [Distance.foo] = Distance.foo, [Distance.bar] = Distance.bar, [Distance.baz] = Distance.baz };
 
-                instance.Far_set_list = new THashSet<List<Distance>>() { new List<Distance>() { Distance.foo } };
-                instance.Far_list_map_set = new List<Dictionary<sbyte, THashSet<Distance>>>() { new Dictionary<sbyte, THashSet<Distance>>() { [1] = new THashSet<Distance>() { Distance.baz } } };
-                instance.Far_map_dist_to_rds = new Dictionary<Distance, List<RaceDetails>>() { [Distance.bar] = new List<RaceDetails>() { MakeNestedRaceDetails(nesting) } };
+                instance.Far_set_list = new HashSet<List<Distance>>() { new List<Distance>() { Distance.foo } };
+                instance.Far_list_map_set = new List<Dictionary<sbyte, HashSet<Distance>>>() { new Dictionary<sbyte, HashSet<Distance>>() { [1] = new HashSet<Distance>() { Distance.baz } } };
+
+                instance.Far_map_dist_to_rds = new Dictionary<Distance, List<RaceDetails>>() { [Distance.bar] = new List<RaceDetails>()  };
+                var details = MakeNestedRaceDetails(nesting);
+                if (details != null)
+                    instance.Far_map_dist_to_rds[Distance.bar].Add(details);
 
                 instance.Req_nested = MakeNestedRaceDetails(nesting);
                 Assert.IsFalse(instance.__isset.opt_nested);
@@ -245,19 +247,19 @@
             instance.Triplesix = ModifyValue(instance.Triplesix);
         }
 
-        private jack ModifyValue(jack value, int level)
+        private jack? ModifyValue(jack? value, int level)
         {
             if (++level > 4)
                 return value;
 
             if (value == null)
                 value = MakeNestedUnion(0);
-            Debug.Assert(value.As_nested_struct != null);
+            Debug.Assert(value?.As_nested_struct != null);
             ModifyInstance(value.As_nested_struct, level);
             return value;
         }
 
-        private RaceDetails ModifyValue(RaceDetails value, int level)
+        private RaceDetails? ModifyValue(RaceDetails? value, int level)
         {
             if (++level > 4)
                 return value;
@@ -268,7 +270,7 @@
             return value;
         }
 
-        private Dictionary<Distance, List<RaceDetails>> ModifyValue(Dictionary<Distance, List<RaceDetails>> value, int level)
+        private Dictionary<Distance, List<RaceDetails>> ModifyValue(Dictionary<Distance, List<RaceDetails>>? value, int level)
         {
             if (value == null)
                 value = new Dictionary<Distance, List<RaceDetails>>();
@@ -283,29 +285,30 @@
             if (value.TryGetValue(Distance.bar, out var list) && (list.Count > 0))
             {
                 ModifyInstance(list[0], level);
-                list.Add(null);
+                //list.Add(null);  -- Thrift does not allow null values in containers
             }
 
-            value[Distance.baz] = null;
+            // Thrift does not allow null values in containers
+            //value[Distance.baz] = null;
 
             return value;
         }
 
-        private static List<Dictionary<sbyte, THashSet<Distance>>> ModifyValue(List<Dictionary<sbyte, THashSet<Distance>>> value)
+        private static List<Dictionary<sbyte, HashSet<Distance>>> ModifyValue(List<Dictionary<sbyte, HashSet<Distance>>>? value)
         {
             if (value == null)
-                value = new List<Dictionary<sbyte, THashSet<Distance>>>();
+                value = new List<Dictionary<sbyte, HashSet<Distance>>>();
 
             if (value.Count == 0)
-                value.Add(new Dictionary<sbyte, THashSet<Distance>>());
-            else
-                value.Add(null);
+                value.Add(new Dictionary<sbyte, HashSet<Distance>>());
+            //else
+            //value.Add(null); --Thrift does not allow null values in containers
 
             sbyte key = (sbyte)(value[0].Count + 10);
             if (value[0].Count == 0)
-                value[0].Add(key, new THashSet<Distance>());
-            else
-                value[0].Add(key, null);
+                value[0].Add(key, new HashSet<Distance>());
+            //else
+            //value[0].Add(key, null); --Thrift does not allow null values in containers
 
             foreach (var entry in value)
             {
@@ -327,15 +330,15 @@
             return value;
         }
 
-        private static THashSet<List<Distance>> ModifyValue(THashSet<List<Distance>> value)
+        private static HashSet<List<Distance>> ModifyValue(HashSet<List<Distance>>? value)
         {
             if (value == null)
-                value = new THashSet<List<Distance>>();
+                value = new HashSet<List<Distance>>();
 
             if (value.Count == 0)
                 value.Add(new List<Distance>());
-            else
-                value.Add(null);
+            //else
+            //value.Add(null); -- Thrift does not allow null values in containers
 
             foreach (var entry in value)
                 if( entry != null)
@@ -344,7 +347,7 @@
             return value;
         }
 
-        private static Dictionary<Distance, Distance> ModifyValue(Dictionary<Distance, Distance> value)
+        private static Dictionary<Distance, Distance> ModifyValue(Dictionary<Distance, Distance>? value)
         {
             if (value == null)
                 value = new Dictionary<Distance, Distance>();
@@ -354,10 +357,10 @@
             return value;
         }
 
-        private static THashSet<Distance> ModifyValue(THashSet<Distance> value)
+        private static HashSet<Distance> ModifyValue(HashSet<Distance>? value)
         {
             if (value == null)
-                value = new THashSet<Distance>();
+                value = new HashSet<Distance>();
 
             if (value.Contains(Distance.foo))
                 value.Remove(Distance.foo);
@@ -377,7 +380,7 @@
             return value;
         }
 
-        private static List<Distance> ModifyValue(List<Distance> value)
+        private static List<Distance> ModifyValue(List<Distance>? value)
         {
             if (value == null)
                 value = new List<Distance>();
@@ -392,7 +395,7 @@
             return !value;
         }
 
-        private static Dictionary<sbyte, short> ModifyValue(Dictionary<sbyte, short> value)
+        private static Dictionary<sbyte, short> ModifyValue(Dictionary<sbyte, short>? value)
         {
             if (value == null)
                 value = new Dictionary<sbyte, short>();
@@ -400,15 +403,15 @@
             return value;
         }
 
-        private static THashSet<long> ModifyValue(THashSet<long> value)
+        private static HashSet<long> ModifyValue(HashSet<long>? value)
         {
             if (value == null)
-                value = new THashSet<long>();
+                value = new HashSet<long>();
             value.Add(value.Count+100);
             return value;
         }
 
-        private static List<int> ModifyValue(List<int> value)
+        private static List<int> ModifyValue(List<int>? value)
         {
             if (value == null)
                 value = new List<int>();
@@ -416,16 +419,18 @@
             return value;
         }
 
-        private static byte[] ModifyValue(byte[] value)
+        private static byte[] ModifyValue(byte[]? value)
         {
             if (value == null)
                 value = new byte[1] { 0 };
             if (value.Length > 0)
                 value[0] = (value[0] < 0xFF) ? ++value[0] : (byte)0;
+            else
+                value = new byte[1] { 0 };
             return value;
         }
 
-        private static string ModifyValue(string value)
+        private static string ModifyValue(string? value)
         {
             return value + "1";
         }
diff --git a/lib/netstd/Tests/Thrift.Tests/DataModel/NullValuesSet.cs b/lib/netstd/Tests/Thrift.Tests/DataModel/NullValuesSet.cs
index 693b68e..ebc1717 100644
--- a/lib/netstd/Tests/Thrift.Tests/DataModel/NullValuesSet.cs
+++ b/lib/netstd/Tests/Thrift.Tests/DataModel/NullValuesSet.cs
@@ -25,13 +25,15 @@
 using OptReqDefTest;
 using Thrift.Collections;
 
+#pragma warning disable IDE0017  // init can be simplified - we don't want that here
+
 namespace Thrift.Tests.DataModel
 {
     // ReSharper disable once InconsistentNaming
     [TestClass]
     public class Thrift_5238
     {
-        private void CheckInstance(RaceDetails instance)
+        private static void CheckInstance(RaceDetails instance)
         {
             // object
             Assert.IsTrue(instance.__isset.def_nested);
@@ -42,14 +44,14 @@
             // string
             Assert.IsTrue(instance.__isset.def_four);
             Assert.IsTrue(instance.__isset.opt_four);
-            Assert.IsNull(instance.Req_four);
+            Assert.IsTrue(string.IsNullOrEmpty(instance.Req_four));
             Assert.IsNull(instance.Def_four);
             Assert.IsNull(instance.Opt_four);
 
             // byte[]
             Assert.IsTrue(instance.__isset.def_five);
             Assert.IsTrue(instance.__isset.opt_five);
-            Assert.IsNull(instance.Req_five);
+            Assert.IsTrue((instance.Req_five == null) || (instance.Req_five.Length == 0));
             Assert.IsNull(instance.Def_five);
             Assert.IsNull(instance.Opt_five);
 
@@ -66,6 +68,9 @@
         {
             var instance = new OptReqDefTest.RaceDetails();
 
+            // the following code INTENTIONALLY assigns null to non.nullable reftypes
+            #pragma warning disable CS8625
+
             // object
             instance.Def_nested = null;
             instance.Opt_nested = null;
@@ -85,6 +90,9 @@
             instance.Opt_six = null;
             instance.Def_six = null;
 
+            // back to normal
+            #pragma warning restore CS8625
+
             // test the setup
             CheckInstance(instance);
 
diff --git a/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj b/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj
index 38a6a5c..27edf7b 100644
--- a/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj
+++ b/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj
@@ -20,7 +20,7 @@
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
-    <Version>0.16.0.0</Version>
+    <Version>0.17.0.0</Version>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
diff --git a/lib/netstd/Thrift/Collections/THashSet.cs b/lib/netstd/Thrift/Collections/THashSet.cs
index 1c060e5..fc2a507 100644
--- a/lib/netstd/Thrift/Collections/THashSet.cs
+++ b/lib/netstd/Thrift/Collections/THashSet.cs
@@ -15,69 +15,37 @@
 // specific language governing permissions and limitations
 // under the License.
 
+using System;
 using System.Collections;
 using System.Collections.Generic;
 
 namespace Thrift.Collections
 {
     // ReSharper disable once InconsistentNaming
-    public class THashSet<T> : ICollection<T>
+	[Obsolete("deprecated, use HashSet<T> instead")]
+    public class THashSet<T> : System.Collections.Generic.HashSet<T>
     {
-        private readonly HashSet<T> Items;
-
         public THashSet()
+            : base()
         {
-            Items = new HashSet<T>();
         }
 
         public THashSet(int capacity)
+#if NET5_0_OR_GREATER
+            : base(capacity)
+#elif NETFRAMEWORK || NETSTANDARD
+            : base(/*capacity not supported*/)
+#else
+#error Unknown platform
+#endif
         {
-            #if NET5_0_OR_GREATER
-            Items = new HashSet<T>(capacity);
-            #elif NETFRAMEWORK || NETSTANDARD
-            Items = new HashSet<T>(/*capacity not supported*/);
-            #else
-            #error Unknown platform
-            #endif
         }
 
-        public int Count => Items.Count;
-
-        public bool IsReadOnly => false;
-
-        public void Add(T item)
+        public THashSet(IEnumerable<T> collection)
+            : base(collection)
         {
-            Items.Add(item);
         }
 
-        public void Clear()
-        {
-            Items.Clear();
-        }
-
-        public bool Contains(T item)
-        {
-            return Items.Contains(item);
-        }
-
-        public void CopyTo(T[] array, int arrayIndex)
-        {
-            Items.CopyTo(array, arrayIndex);
-        }
-
-        IEnumerator IEnumerable.GetEnumerator()
-        {
-            return Items.GetEnumerator();
-        }
-
-        public IEnumerator<T> GetEnumerator()
-        {
-            return ((IEnumerable<T>) Items).GetEnumerator();
-        }
-
-        public bool Remove(T item)
-        {
-            return Items.Remove(item);
-        }
     }
 }
+
diff --git a/lib/netstd/Thrift/Properties/AssemblyInfo.cs b/lib/netstd/Thrift/Properties/AssemblyInfo.cs
index 50fa031..5aa368f 100644
--- a/lib/netstd/Thrift/Properties/AssemblyInfo.cs
+++ b/lib/netstd/Thrift/Properties/AssemblyInfo.cs
@@ -52,5 +52,5 @@
 // You can specify all the values or you can default the Build and Revision Numbers
 // by using the '*' as shown below:
 
-[assembly: AssemblyVersion("0.16.0.0")]
-[assembly: AssemblyFileVersion("0.16.0.0")]
+[assembly: AssemblyVersion("0.17.0.0")]
+[assembly: AssemblyFileVersion("0.17.0.0")]
diff --git a/lib/netstd/Thrift/Thrift.csproj b/lib/netstd/Thrift/Thrift.csproj
index 162f475..cf06452 100644
--- a/lib/netstd/Thrift/Thrift.csproj
+++ b/lib/netstd/Thrift/Thrift.csproj
@@ -40,8 +40,8 @@
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>thrift.snk</AssemblyOriginatorKeyFile>
     <DelaySign>false</DelaySign>
-    <Title>Apache Thrift 0.16.0</Title>
-    <Version>0.16.0.0</Version>
+    <Title>Apache Thrift 0.17.0</Title>
+    <Version>0.17.0.0</Version>
     <GeneratePackageOnBuild>false</GeneratePackageOnBuild>
     <PackageProjectUrl>http://thrift.apache.org/</PackageProjectUrl>
     <Authors>Apache Thrift Developers</Authors>
@@ -50,7 +50,7 @@
     <PackageDescription>C# .NET Core bindings for the Apache Thrift RPC system</PackageDescription>
     <PackageReleaseNotes></PackageReleaseNotes>
     <PackageTags>Apache Thrift RPC</PackageTags>
-    <PackageReleaseNotes>https://github.com/apache/thrift/blob/0.16.0/CHANGES.md</PackageReleaseNotes>
+    <PackageReleaseNotes>https://github.com/apache/thrift/blob/0.17.0/CHANGES.md</PackageReleaseNotes>
     <Copyright>Copyright 2022 The Apache Software Foundation</Copyright>
   </PropertyGroup>
 
diff --git a/lib/netstd/Thrift/Transport/Client/TStreamTransport.cs b/lib/netstd/Thrift/Transport/Client/TStreamTransport.cs
index 90794c6..053a37b 100644
--- a/lib/netstd/Thrift/Transport/Client/TStreamTransport.cs
+++ b/lib/netstd/Thrift/Transport/Client/TStreamTransport.cs
@@ -80,11 +80,8 @@
                     "Cannot read from null inputstream");
             }
 
-#if NETSTANDARD2_0
-            return await InputStream.ReadAsync(buffer, offset, length, cancellationToken);
-#else
-            return await InputStream.ReadAsync(new Memory<byte>(buffer, offset, length), cancellationToken);
-#endif
+            // The ReadAsync method should not be used since it does not check the ReceiveTimeout property.
+            return await Task.Run( () => InputStream.Read( buffer, offset, length ), cancellationToken );
         }
 
         public override async Task WriteAsync(byte[] buffer, int offset, int length, CancellationToken cancellationToken)
@@ -95,11 +92,8 @@
                     "Cannot write to null outputstream");
             }
 
-#if NETSTANDARD2_0
-            await OutputStream.WriteAsync(buffer, offset, length, cancellationToken);
-#else
-            await OutputStream.WriteAsync(buffer.AsMemory(offset, length), cancellationToken);
-#endif
+            // The WriteAsync method should not be used since it does not check the SendTimeout property.
+            await Task.Run( () => OutputStream.Write( buffer, offset, length ), cancellationToken );
         }
 
         public override async Task FlushAsync(CancellationToken cancellationToken)
diff --git a/lib/ocaml/_oasis b/lib/ocaml/_oasis
index e901466..56374e0 100644
--- a/lib/ocaml/_oasis
+++ b/lib/ocaml/_oasis
@@ -1,5 +1,5 @@
 Name: libthrift-ocaml
-Version: 0.16.0
+Version: 0.17.0
 OASISFormat: 0.3
 Synopsis: OCaml bindings for the Apache Thrift RPC system
 Authors: Apache Thrift Developers <dev@thrift.apache.org>
diff --git a/lib/perl/lib/Thrift.pm b/lib/perl/lib/Thrift.pm
index b04cd21..e7e1f0c 100644
--- a/lib/perl/lib/Thrift.pm
+++ b/lib/perl/lib/Thrift.pm
@@ -31,6 +31,6 @@
 #
 
 package Thrift;
-use version 0.77; our $VERSION = version->declare("v0.16.0");
+use version 0.77; our $VERSION = version->declare("v0.17.0");
 
 1;
diff --git a/lib/py/setup.py b/lib/py/setup.py
index 7cd4a2e..bba69c8 100644
--- a/lib/py/setup.py
+++ b/lib/py/setup.py
@@ -105,7 +105,7 @@
     twisted_deps = ['twisted']
 
     setup(name='thrift',
-          version='0.16.0',
+          version='0.17.0',
           description='Python bindings for the Apache Thrift RPC system',
           long_description=read_file("README.md"),
           long_description_content_type="text/markdown",
diff --git a/lib/py/src/ext/endian.h b/lib/py/src/ext/endian.h
index 1660cbd..a2cf594 100644
--- a/lib/py/src/ext/endian.h
+++ b/lib/py/src/ext/endian.h
@@ -25,7 +25,7 @@
 #ifndef _WIN32
 #include <netinet/in.h>
 #else
-#include <WinSock2.h>
+#include <winsock2.h>
 #pragma comment(lib, "ws2_32.lib")
 #define BIG_ENDIAN (4321)
 #define LITTLE_ENDIAN (1234)
diff --git a/lib/py/src/transport/THttpClient.py b/lib/py/src/transport/THttpClient.py
index 212da3a..b131690 100644
--- a/lib/py/src/transport/THttpClient.py
+++ b/lib/py/src/transport/THttpClient.py
@@ -98,7 +98,7 @@
             return None
         ap = "%s:%s" % (urllib.parse.unquote(proxy.username),
                         urllib.parse.unquote(proxy.password))
-        cr = base64.b64encode(ap).strip()
+        cr = base64.b64encode(ap.encode()).strip()
         return "Basic " + cr
 
     def using_proxy(self):
diff --git a/lib/rb/thrift.gemspec b/lib/rb/thrift.gemspec
index 26fa86b..150b959 100644
--- a/lib/rb/thrift.gemspec
+++ b/lib/rb/thrift.gemspec
@@ -3,7 +3,7 @@
 
 Gem::Specification.new do |s|
   s.name        = 'thrift'
-  s.version     = '0.16.0'
+  s.version     = '0.17.0'
   s.authors     = ['Apache Thrift Developers']
   s.email       = ['dev@thrift.apache.org']
   s.homepage    = 'http://thrift.apache.org'
diff --git a/lib/rs/Cargo.toml b/lib/rs/Cargo.toml
index a32d671..4aedaec 100644
--- a/lib/rs/Cargo.toml
+++ b/lib/rs/Cargo.toml
@@ -2,7 +2,7 @@
 name = "thrift"
 description = "Rust bindings for the Apache Thrift RPC system"
 edition = "2018"
-version = "0.16.0"
+version = "0.17.0"
 license = "Apache-2.0"
 authors = ["Apache Thrift Developers <dev@thrift.apache.org>"]
 homepage = "http://thrift.apache.org"
diff --git a/lib/rs/src/protocol/binary.rs b/lib/rs/src/protocol/binary.rs
index 8509c34..9f8af43 100644
--- a/lib/rs/src/protocol/binary.rs
+++ b/lib/rs/src/protocol/binary.rs
@@ -84,7 +84,7 @@
         // the thrift version header is intentionally negative
         // so the first check we'll do is see if the sign bit is set
         // and if so - assume it's the protocol-version header
-        if first_bytes[0] >= 8 {
+        if (first_bytes[0] & 0x80) != 0 {
             // apparently we got a protocol-version header - check
             // it, and if it matches, read the rest of the fields
             if first_bytes[0..2] != [0x80, 0x01] {
diff --git a/lib/st/package.xml b/lib/st/package.xml
index 134dff2..70cf0ac 100644
--- a/lib/st/package.xml
+++ b/lib/st/package.xml
@@ -17,7 +17,7 @@
  specific language governing permissions and limitations
  under the License.
  -->
-<!-- Apache Thrift Smalltalk library version 0.16.0 -->
+<!-- Apache Thrift Smalltalk library version 0.17.0 -->
 <package>
   <name>libthrift-st</name>
   <file>thrift.st</file>
diff --git a/lib/swift/Sources/Thrift.swift b/lib/swift/Sources/Thrift.swift
index e9be5ee..82b0421 100644
--- a/lib/swift/Sources/Thrift.swift
+++ b/lib/swift/Sources/Thrift.swift
@@ -1,3 +1,3 @@
 class Thrift {
-	let version = "0.16.0"
+	let version = "0.17.0"
 }
diff --git a/lib/swift/Tests/ThriftTests/ThriftTests.swift b/lib/swift/Tests/ThriftTests/ThriftTests.swift
index 91a43ee..d19c89d 100644
--- a/lib/swift/Tests/ThriftTests/ThriftTests.swift
+++ b/lib/swift/Tests/ThriftTests/ThriftTests.swift
@@ -3,7 +3,7 @@
 
 class ThriftTests: XCTestCase {
   func testVersion() {
-    XCTAssertEqual(Thrift().version, "0.16.0")
+    XCTAssertEqual(Thrift().version, "0.17.0")
   }
 
   static var allTests : [(String, (ThriftTests) -> () throws -> Void)] {
diff --git a/lib/ts/package-lock.json b/lib/ts/package-lock.json
index 041589b..19658c1 100644
--- a/lib/ts/package-lock.json
+++ b/lib/ts/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "thrift",
-  "version": "0.16.0",
+  "version": "0.17.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/lib/ts/package.json b/lib/ts/package.json
index 268d0c6..8a564c6 100644
--- a/lib/ts/package.json
+++ b/lib/ts/package.json
@@ -1,6 +1,6 @@
 {
   "name": "thrift",
-  "version": "0.16.0",
+  "version": "0.17.0",
   "description": "Thrift is a software framework for scalable cross-language services development.",
   "author": {
     "name": "Apache Thrift Developers",
diff --git a/package-lock.json b/package-lock.json
index 1c8b2ae..161b8fe 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "thrift",
-  "version": "0.16.0",
+  "version": "0.17.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 4ea721e..8f2e1c8 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,7 @@
     "type": "git",
     "url": "https://github.com/apache/thrift.git"
   },
-  "version": "0.16.0",
+  "version": "0.17.0",
   "author": {
     "name": "Apache Thrift Developers",
     "email": "dev@thrift.apache.org",
diff --git a/sonar-project.properties b/sonar-project.properties
index 6c6c8f2..08d4c4a 100755
--- a/sonar-project.properties
+++ b/sonar-project.properties
@@ -16,7 +16,7 @@
 services that work efficiently and seamlessly between all major languages.
 
 # Apache Thrift Version
-sonar.projectVersion=0.16.0
+sonar.projectVersion=0.17.0
 # use this to set another version string
 # $ sonar-runner -D sonar.projectVersion=`git rev-parse HEAD`
 # set projectDate in combination with projectVersion for imports of old releases
@@ -54,7 +54,7 @@
 module1.sonar.projectBaseDir=lib/java
 module1.sonar.sources=src
 module1.sonar.tests=test
-module1.sonar.binaries=build/libs/libthrift-0.16.0.jar
+module1.sonar.binaries=build/libs/libthrift-0.17.0.jar
 module1.sonar.libraries=build/deps/*.jar
 module1.sonar.language=java
 
@@ -62,7 +62,7 @@
 module2.sonar.projectBaseDir=.
 module2.sonar.sources=tutorial/java/src, tutorial/java/gen-java
 module2.sonar.binaries=tutorial/java/tutorial.jar
-module2.sonar.libraries=lib/java/build/deps/*.jar,lib/java/build/libs/libthrift-0.16.0.jar
+module2.sonar.libraries=lib/java/build/deps/*.jar,lib/java/build/libs/libthrift-0.17.0.jar
 module2.sonar.language=java
 
 module3.sonar.projectName=Apache Thrift - JavaScript Library
diff --git a/test/Makefile.am b/test/Makefile.am
index b289e53..2199f1e 100755
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -167,6 +167,7 @@
 	UnsafeTypes.thrift \
 	Service.thrift \
 	SpecificNameTest.thrift \
+	partial/thrift_test_schema.thrift \
 	known_failures_Linux.json \
 	test.py \
 	tests.json \
diff --git a/test/dart/test_client/pubspec.yaml b/test/dart/test_client/pubspec.yaml
index d5848b4..2898169 100644
--- a/test/dart/test_client/pubspec.yaml
+++ b/test/dart/test_client/pubspec.yaml
@@ -16,7 +16,7 @@
 # under the License.
 
 name: thrift_test_client
-version: 0.16.0
+version: 0.17.0
 description: A client integration test for the Dart Thrift library
 author: Apache Thrift Developers <dev@thrift.apache.org>
 homepage: http://thrift.apache.org
diff --git a/test/erl/src/thrift_test.app.src b/test/erl/src/thrift_test.app.src
index 6faa1b5..60f7f14 100644
--- a/test/erl/src/thrift_test.app.src
+++ b/test/erl/src/thrift_test.app.src
@@ -22,7 +22,7 @@
   {description, "Thrift cross language test"},
 
   % The version of the applicaton
-  {vsn, "0.16.0"},
+  {vsn, "0.17.0"},
 
   % All modules used by the application.
   {modules, [
diff --git a/test/netstd/Client/Client.csproj b/test/netstd/Client/Client.csproj
index 859297f..9d4ab48 100644
--- a/test/netstd/Client/Client.csproj
+++ b/test/netstd/Client/Client.csproj
@@ -24,7 +24,7 @@
     <AssemblyName>Client</AssemblyName>
     <PackageId>Client</PackageId>
     <OutputType>Exe</OutputType>
-    <Version>0.16.0.0</Version>
+    <Version>0.17.0.0</Version>
     <GenerateAssemblyTitleAttribute>false</GenerateAssemblyTitleAttribute>
     <GenerateAssemblyDescriptionAttribute>false</GenerateAssemblyDescriptionAttribute>
     <GenerateAssemblyConfigurationAttribute>false</GenerateAssemblyConfigurationAttribute>
@@ -49,8 +49,8 @@
     <Exec Condition="'$(OS)' == 'Windows_NT'" Command="where thrift" ConsoleToMSBuild="true">
       <Output TaskParameter="ConsoleOutput" PropertyName="PathToThrift" />
     </Exec>
-    <Exec Condition="Exists('$(PathToThrift)')" Command="&quot;$(PathToThrift)&quot; -out $(ProjectDir) -gen netstd:wcf,union,serial -r ./../../ThriftTest.thrift" />
-    <Exec Condition="Exists('thrift')" Command="thrift -out $(ProjectDir) -gen netstd:wcf,union,serial -r ./../../ThriftTest.thrift" />
-    <Exec Condition="Exists('$(ProjectDir)/../../../compiler/cpp/thrift')" Command="$(ProjectDir)/../../../compiler/cpp/thrift -out $(ProjectDir) -gen netstd:wcf,union,serial -r ./../../ThriftTest.thrift" />
+    <Exec Condition="Exists('$(PathToThrift)')" Command="&quot;$(PathToThrift)&quot; -out $(ProjectDir) -gen netstd:wcf,union,serial,net6 -r ./../../ThriftTest.thrift" />
+    <Exec Condition="Exists('thrift')" Command="thrift -out $(ProjectDir) -gen netstd:wcf,union,serial,net6 -r ./../../ThriftTest.thrift" />
+    <Exec Condition="Exists('$(ProjectDir)/../../../compiler/cpp/thrift')" Command="$(ProjectDir)/../../../compiler/cpp/thrift -out $(ProjectDir) -gen netstd:wcf,union,serial,net6 -r ./../../ThriftTest.thrift" />
   </Target>
 </Project>
diff --git a/test/netstd/Client/Performance/TestDataFactory.cs b/test/netstd/Client/Performance/TestDataFactory.cs
index 833947c..8dec3f3 100644
--- a/test/netstd/Client/Performance/TestDataFactory.cs
+++ b/test/netstd/Client/Performance/TestDataFactory.cs
@@ -40,9 +40,9 @@
             };
         }
 
-        private static THashSet<Insanity> CreateSetField(int count)
+        private static HashSet<Insanity> CreateSetField(int count)
         {
-            var retval = new THashSet<Insanity>();
+            var retval = new HashSet<Insanity>();
             for (var i = 0; i < count; ++i)
                 retval.Add(CreateInsanity(count));
             return retval;
@@ -90,41 +90,41 @@
             return retval;
         }
 
-        private static List<Dictionary<THashSet<int>, Dictionary<int, THashSet<List<Dictionary<Insanity, string>>>>>> CreateListField(int count)
+        private static List<Dictionary<HashSet<int>, Dictionary<int, HashSet<List<Dictionary<Insanity, string>>>>>> CreateListField(int count)
         {
-            var retval = new List<Dictionary<THashSet<int>, Dictionary<int, THashSet<List<Dictionary<Insanity, string>>>>>>();
+            var retval = new List<Dictionary<HashSet<int>, Dictionary<int, HashSet<List<Dictionary<Insanity, string>>>>>>();
             for (var i = 0; i < count; ++i)
                 retval.Add(CreateListFieldData(count));
             return retval;
         }
 
-        private static Dictionary<THashSet<int>, Dictionary<int, THashSet<List<Dictionary<Insanity, string>>>>> CreateListFieldData(int count)
+        private static Dictionary<HashSet<int>, Dictionary<int, HashSet<List<Dictionary<Insanity, string>>>>> CreateListFieldData(int count)
         {
-            var retval = new Dictionary<THashSet<int>, Dictionary<int, THashSet<List<Dictionary<Insanity, string>>>>>();
+            var retval = new Dictionary<HashSet<int>, Dictionary<int, HashSet<List<Dictionary<Insanity, string>>>>>();
             for (var i = 0; i < count; ++i)
                 retval.Add( CreateIntHashSet(count), CreateListFieldDataDict(count));
             return retval;
         }
 
-        private static THashSet<int> CreateIntHashSet(int count)
+        private static HashSet<int> CreateIntHashSet(int count)
         {
-            var retval = new THashSet<int>();
+            var retval = new HashSet<int>();
             for (var i = 0; i < count; ++i)
                 retval.Add(i);
             return retval;
         }
 
-        private static Dictionary<int, THashSet<List<Dictionary<Insanity, string>>>> CreateListFieldDataDict(int count)
+        private static Dictionary<int, HashSet<List<Dictionary<Insanity, string>>>> CreateListFieldDataDict(int count)
         {
-            var retval = new Dictionary<int, THashSet<List<Dictionary<Insanity, string>>>>();
+            var retval = new Dictionary<int, HashSet<List<Dictionary<Insanity, string>>>>();
             for (var i = 0; i < count; ++i)
                 retval.Add(i, CreateListFieldDataDictValue(count));
             return retval;
         }
 
-        private static THashSet<List<Dictionary<Insanity, string>>> CreateListFieldDataDictValue(int count)
+        private static HashSet<List<Dictionary<Insanity, string>>> CreateListFieldDataDictValue(int count)
         {
-            var retval = new THashSet<List<Dictionary<Insanity, string>>>();
+            var retval = new HashSet<List<Dictionary<Insanity, string>>>();
             for (var i = 0; i < count; ++i)
                 retval.Add( CreateListFieldDataDictValueList(count));
             return retval;
diff --git a/test/netstd/Client/TestClient.cs b/test/netstd/Client/TestClient.cs
index 0a7fa00..29c0d2e 100644
--- a/test/netstd/Client/TestClient.cs
+++ b/test/netstd/Client/TestClient.cs
@@ -411,15 +411,28 @@
                     return ErrorUnknown;
                 }
 
-                var tests = Enumerable.Range(0, param.numThreads).Select(_ => new ClientTest(param)).ToArray();
-
                 //issue tests on separate threads simultaneously
+                var nThreads = Math.Max(param.numThreads, 1);
+                Console.Write("Starting {0} test thread(s) ", nThreads);
+                var tasks = new Task[nThreads];
                 var start = DateTime.Now;
-                var tasks = tests.Select(test => test.Execute()).ToArray();
+                var retcode = 0;
+                for (var i = 0; i < tasks.Length; ++i)
+                {
+                    Console.Write('.');
+                    tasks[i] = Task.Run(async () =>
+                    {
+                        var test = new ClientTest(param);
+                        await test.Execute();
+                        lock (tasks)
+                            retcode |= test.ReturnCode;
+                    });
+                }
+                Console.WriteLine(" OK");
                 Task.WaitAll(tasks);
                 Console.WriteLine("Total time: " + (DateTime.Now - start));
                 Console.WriteLine();
-                return tests.Select(t => t.ReturnCode).Aggregate((r1, r2) => r1 | r2);
+                return retcode;
             }
             catch (Exception outerEx)
             {
@@ -490,7 +503,7 @@
             return retval;
         }
 
-        private static CancellationToken MakeTimeoutToken(int msec = 5000)
+        private static CancellationToken MakeTimeoutToken(int msec = 15_000)
         {
             var token = new CancellationTokenSource(msec);
             return token.Token;
@@ -644,9 +657,14 @@
                 Struct_thing = o,
                 I32_thing = 5
             };
-            var i2 = await client.testNest(o2, MakeTimeoutToken());
+            Xtruct2 i2 = await client.testNest(o2, MakeTimeoutToken());
             i = i2.Struct_thing;
-            Console.WriteLine(" = {" + i2.Byte_thing + ", {\"" + i.String_thing + "\", " + i.Byte_thing + ", " + i.I32_thing + ", " + i.I64_thing + "}, " + i2.I32_thing + "}");
+            Console.WriteLine(" = {" + i2.Byte_thing + ", {\""
+                            + (i?.String_thing ?? "<null>") + "\", "
+                            + (i?.Byte_thing ?? 0) + ", "
+                            + (i?.I32_thing ?? 0) + ", "
+                            + (i?.I64_thing ?? 0) + "}, "
+                            + i2.I32_thing + "}");
 
             var mapout = new Dictionary<int, int>();
             for (var j = 0; j < 5; j++)
@@ -681,7 +699,7 @@
 
             //set
             // TODO: Validate received message
-            var setout = new THashSet<int>();
+            var setout = new HashSet<int>();
             for (var j = -2; j < 3; j++)
             {
                 setout.Add(j);
@@ -937,7 +955,7 @@
             }
             catch (Xception2 ex)
             {
-                if (ex.ErrorCode != 2002 || ex.Struct_thing.String_thing != "This is an Xception2")
+                if (ex.ErrorCode != 2002 || ex.Struct_thing?.String_thing != "This is an Xception2")
                 {
                     Console.WriteLine("*** FAILED ***");
                     returnCode |= ErrorExceptions;
diff --git a/test/netstd/Server/Server.csproj b/test/netstd/Server/Server.csproj
index cda1dff..439e5c1 100644
--- a/test/netstd/Server/Server.csproj
+++ b/test/netstd/Server/Server.csproj
@@ -24,7 +24,7 @@
     <AssemblyName>Server</AssemblyName>
     <PackageId>Server</PackageId>
     <OutputType>Exe</OutputType>
-    <Version>0.16.0.0</Version>
+    <Version>0.17.0.0</Version>
     <GenerateAssemblyTitleAttribute>false</GenerateAssemblyTitleAttribute>
     <GenerateAssemblyDescriptionAttribute>false</GenerateAssemblyDescriptionAttribute>
     <GenerateAssemblyConfigurationAttribute>false</GenerateAssemblyConfigurationAttribute>
@@ -51,8 +51,8 @@
     <Exec Condition="'$(OS)' == 'Windows_NT'" Command="where thrift" ConsoleToMSBuild="true">
       <Output TaskParameter="ConsoleOutput" PropertyName="PathToThrift" />
     </Exec>
-    <Exec Condition="Exists('$(PathToThrift)')" Command="&quot;$(PathToThrift)&quot; -out $(ProjectDir) -gen netstd:wcf,union,serial -r ./../../ThriftTest.thrift" />
-    <Exec Condition="Exists('thrift')" Command="thrift -out $(ProjectDir) -gen netstd:wcf,union,serial -r ./../../ThriftTest.thrift" />
-    <Exec Condition="Exists('$(ProjectDir)/../../../compiler/cpp/thrift')" Command="$(ProjectDir)/../../../compiler/cpp/thrift -out $(ProjectDir) -gen netstd:wcf,union,serial -r ./../../ThriftTest.thrift" />
+    <Exec Condition="Exists('$(PathToThrift)')" Command="&quot;$(PathToThrift)&quot; -out $(ProjectDir) -gen netstd:wcf,union,serial,net6 -r ./../../ThriftTest.thrift" />
+    <Exec Condition="Exists('thrift')" Command="thrift -out $(ProjectDir) -gen netstd:wcf,union,serial,net6 -r ./../../ThriftTest.thrift" />
+    <Exec Condition="Exists('$(ProjectDir)/../../../compiler/cpp/thrift')" Command="$(ProjectDir)/../../../compiler/cpp/thrift -out $(ProjectDir) -gen netstd:wcf,union,serial,net6 -r ./../../ThriftTest.thrift" />
   </Target>
 </Project>
diff --git a/test/netstd/Server/TestServer.cs b/test/netstd/Server/TestServer.cs
index 515a299..86072b0 100644
--- a/test/netstd/Server/TestServer.cs
+++ b/test/netstd/Server/TestServer.cs
@@ -229,10 +229,10 @@
                 return Task.CompletedTask;
             }
 
-            public Task<string> testString(string thing, CancellationToken cancellationToken)
+            public Task<string> testString(string? thing, CancellationToken cancellationToken)
             {
-                logger.Invoke("testString({0})", thing);
-                return Task.FromResult(thing);
+                logger.Invoke("testString({0})", thing ?? "<null>");
+                return Task.FromResult(thing ?? string.Empty);
             }
 
             public Task<bool> testBool(bool thing, CancellationToken cancellationToken)
@@ -265,117 +265,129 @@
                 return Task.FromResult(thing);
             }
 
-            public Task<byte[]> testBinary(byte[] thing, CancellationToken cancellationToken)
+            public Task<byte[]> testBinary(byte[]? thing, CancellationToken cancellationToken)
             {
-                logger.Invoke("testBinary({0} bytes)", thing.Length);
-                return Task.FromResult(thing);
+                logger.Invoke("testBinary({0} bytes)", thing?.Length ?? 0);
+                return Task.FromResult(thing ?? Array.Empty<byte>());
             }
 
-            public Task<Xtruct> testStruct(Xtruct thing, CancellationToken cancellationToken)
+            public Task<Xtruct> testStruct(Xtruct? thing, CancellationToken cancellationToken)
             {
-                logger.Invoke("testStruct({{\"{0}\", {1}, {2}, {3}}})", thing.String_thing, thing.Byte_thing, thing.I32_thing, thing.I64_thing);
-                return Task.FromResult(thing);
+                logger.Invoke("testStruct({{\"{0}\", {1}, {2}, {3}}})", thing?.String_thing ?? "<null>", thing?.Byte_thing ?? 0, thing?.I32_thing ?? 0, thing?.I64_thing ?? 0);
+                return Task.FromResult(thing ?? new Xtruct());   // null returns are not allowed in Thrift
             }
 
-            public Task<Xtruct2> testNest(Xtruct2 nest, CancellationToken cancellationToken)
+            public Task<Xtruct2> testNest(Xtruct2? nest, CancellationToken cancellationToken)
             {
-                var thing = nest.Struct_thing;
+                var thing = nest?.Struct_thing;
                 logger.Invoke("testNest({{{0}, {{\"{1}\", {2}, {3}, {4}, {5}}}}})",
-                    nest.Byte_thing,
-                    thing.String_thing,
-                    thing.Byte_thing,
-                    thing.I32_thing,
-                    thing.I64_thing,
-                    nest.I32_thing);
-                return Task.FromResult(nest);
+                    nest?.Byte_thing ?? 0,
+                    thing?.String_thing ?? "<null>",
+                    thing?.Byte_thing ?? 0,
+                    thing?.I32_thing ?? 0,
+                    thing?.I64_thing ?? 0,
+                    nest?.I32_thing ?? 0);
+                return Task.FromResult(nest ?? new Xtruct2());   // null returns are not allowed in Thrift
             }
 
-            public Task<Dictionary<int, int>> testMap(Dictionary<int, int> thing, CancellationToken cancellationToken)
+            public Task<Dictionary<int, int>> testMap(Dictionary<int, int>? thing, CancellationToken cancellationToken)
             {
                 sb.Clear();
                 sb.Append("testMap({{");
-                var first = true;
-                foreach (var key in thing.Keys)
+                if (thing != null)
                 {
-                    if (first)
+                    var first = true;
+                    foreach (var key in thing.Keys)
                     {
-                        first = false;
+                        if (first)
+                        {
+                            first = false;
+                        }
+                        else
+                        {
+                            sb.Append(", ");
+                        }
+                        sb.AppendFormat("{0} => {1}", key, thing[key]);
                     }
-                    else
-                    {
-                        sb.Append(", ");
-                    }
-                    sb.AppendFormat("{0} => {1}", key, thing[key]);
                 }
                 sb.Append("}})");
                 logger.Invoke(sb.ToString());
-                return Task.FromResult(thing);
+                return Task.FromResult(thing ?? new Dictionary<int, int>());   // null returns are not allowed in Thrift
             }
 
-            public Task<Dictionary<string, string>> testStringMap(Dictionary<string, string> thing, CancellationToken cancellationToken)
+            public Task<Dictionary<string, string>> testStringMap(Dictionary<string, string>? thing, CancellationToken cancellationToken)
             {
                 sb.Clear();
                 sb.Append("testStringMap({{");
-                var first = true;
-                foreach (var key in thing.Keys)
+                if (thing != null)
                 {
-                    if (first)
+                    var first = true;
+                    foreach (var key in thing.Keys)
                     {
-                        first = false;
+                        if (first)
+                        {
+                            first = false;
+                        }
+                        else
+                        {
+                            sb.Append(", ");
+                        }
+                        sb.AppendFormat("{0} => {1}", key, thing[key]);
                     }
-                    else
-                    {
-                        sb.Append(", ");
-                    }
-                    sb.AppendFormat("{0} => {1}", key, thing[key]);
                 }
                 sb.Append("}})");
                 logger.Invoke(sb.ToString());
-                return Task.FromResult(thing);
+                return Task.FromResult(thing ?? new Dictionary<string, string>());   // null returns are not allowed in Thrift
             }
 
-            public Task<THashSet<int>> testSet(THashSet<int> thing, CancellationToken cancellationToken)
+            public Task<HashSet<int>> testSet(HashSet<int>? thing, CancellationToken cancellationToken)
             {
                 sb.Clear();
                 sb.Append("testSet({{");
-                var first = true;
-                foreach (int elem in thing)
+                if (thing != null)
                 {
-                    if (first)
+                    var first = true;
+                    foreach (int elem in thing)
                     {
-                        first = false;
+                        if (first)
+                        {
+                            first = false;
+                        }
+                        else
+                        {
+                            sb.Append(", ");
+                        }
+                        sb.AppendFormat("{0}", elem);
                     }
-                    else
-                    {
-                        sb.Append(", ");
-                    }
-                    sb.AppendFormat("{0}", elem);
                 }
                 sb.Append("}})");
                 logger.Invoke(sb.ToString());
-                return Task.FromResult(thing);
+                return Task.FromResult(thing ?? new HashSet<int>());   // null returns are not allowed in Thrift
             }
 
-            public Task<List<int>> testList(List<int> thing, CancellationToken cancellationToken)
+            public Task<List<int>> testList(List<int>? thing, CancellationToken cancellationToken)
             {
                 sb.Clear();
                 sb.Append("testList({{");
-                var first = true;
-                foreach (var elem in thing)
+                if (thing != null)
                 {
-                    if (first)
+                    var first = true;
+                    foreach (var elem in thing)
                     {
-                        first = false;
+                        if (first)
+                        {
+                            first = false;
+                        }
+                        else
+                        {
+                            sb.Append(", ");
+                        }
+                        sb.AppendFormat("{0}", elem);
                     }
-                    else
-                    {
-                        sb.Append(", ");
-                    }
-                    sb.AppendFormat("{0}", elem);
                 }
                 sb.Append("}})");
                 logger.Invoke(sb.ToString());
-                return Task.FromResult(thing);
+                return Task.FromResult(thing ?? new List<int>());   // null returns are not allowed in Thrift
             }
 
             public Task<Numberz> testEnum(Numberz thing, CancellationToken cancellationToken)
@@ -409,7 +421,7 @@
                 return Task.FromResult(mapmap);
             }
 
-            public Task<Dictionary<long, Dictionary<Numberz, Insanity>>> testInsanity(Insanity argument, CancellationToken cancellationToken)
+            public Task<Dictionary<long, Dictionary<Numberz, Insanity>>> testInsanity(Insanity? argument, CancellationToken cancellationToken)
             {
                 logger.Invoke("testInsanity()");
 
@@ -428,8 +440,9 @@
                 var first_map = new Dictionary<Numberz, Insanity>();
                 var second_map = new Dictionary<Numberz, Insanity>(); ;
 
-                first_map[Numberz.TWO] = argument;
-                first_map[Numberz.THREE] = argument;
+                // null dict keys/values are not allowed in Thrift
+                first_map[Numberz.TWO] = argument ?? new Insanity();
+                first_map[Numberz.THREE] = argument ?? new Insanity();
 
                 second_map[Numberz.SIX] = new Insanity();
 
@@ -442,7 +455,7 @@
                 return Task.FromResult(insane);
             }
 
-            public Task<Xtruct> testMulti(sbyte arg0, int arg1, long arg2, Dictionary<short, string> arg3, Numberz arg4, long arg5,
+            public Task<Xtruct> testMulti(sbyte arg0, int arg1, long arg2, Dictionary<short, string>? arg3, Numberz arg4, long arg5,
                 CancellationToken cancellationToken)
             {
                 logger.Invoke("testMulti()");
@@ -455,9 +468,9 @@
                 return Task.FromResult(hello);
             }
 
-            public Task testException(string arg, CancellationToken cancellationToken)
+            public Task testException(string? arg, CancellationToken cancellationToken)
             {
-                logger.Invoke("testException({0})", arg);
+                logger.Invoke("testException({0})", arg ?? "<null>");
                 if (arg == "Xception")
                 {
                     var x = new Xception
@@ -474,9 +487,9 @@
                 return Task.CompletedTask;
             }
 
-            public Task<Xtruct> testMultiException(string arg0, string arg1, CancellationToken cancellationToken)
+            public Task<Xtruct> testMultiException(string? arg0, string? arg1, CancellationToken cancellationToken)
             {
-                logger.Invoke("testMultiException({0}, {1})", arg0, arg1);
+                logger.Invoke("testMultiException({0}, {1})", arg0 ?? "<null>", arg1 ?? "<null>");
                 if (arg0 == "Xception")
                 {
                     var x = new Xception
diff --git a/tutorial/dart/client/pubspec.yaml b/tutorial/dart/client/pubspec.yaml
index 465bd93..028f003 100644
--- a/tutorial/dart/client/pubspec.yaml
+++ b/tutorial/dart/client/pubspec.yaml
@@ -16,7 +16,7 @@
 # under the License.
 
 name: tutorial_client
-version: 0.16.0
+version: 0.17.0
 description: A Dart client implementation of the Apache Thrift tutorial
 author: Apache Thrift Developers <dev@thrift.apache.org>
 homepage: http://thrift.apache.org
diff --git a/tutorial/dart/console_client/pubspec.yaml b/tutorial/dart/console_client/pubspec.yaml
index 9a8d202..435177f 100644
--- a/tutorial/dart/console_client/pubspec.yaml
+++ b/tutorial/dart/console_client/pubspec.yaml
@@ -16,7 +16,7 @@
 # under the License.
 
 name: tutorial_console_client
-version: 0.16.0
+version: 0.17.0
 description: >
   A Dart console client to implementation of the Apache Thrift tutorial
 author: Apache Thrift Developers <dev@thrift.apache.org>
diff --git a/tutorial/dart/server/pubspec.yaml b/tutorial/dart/server/pubspec.yaml
index 17c4220..0590094 100644
--- a/tutorial/dart/server/pubspec.yaml
+++ b/tutorial/dart/server/pubspec.yaml
@@ -16,7 +16,7 @@
 # under the License.
 
 name: tutorial_server
-version: 0.16.0
+version: 0.17.0
 description: A Dart server to support the Apache Thrift tutorial
 author: Apache Thrift Developers <dev@thrift.apache.org>
 homepage: http://thrift.apache.org
diff --git a/tutorial/delphi/DelphiClient/DelphiClient.dproj b/tutorial/delphi/DelphiClient/DelphiClient.dproj
index cc5170d..ec487e9 100644
--- a/tutorial/delphi/DelphiClient/DelphiClient.dproj
+++ b/tutorial/delphi/DelphiClient/DelphiClient.dproj
@@ -124,13 +124,13 @@
 					<VersionInfoKeys>
 						<VersionInfoKeys Name="CompanyName"/>
 						<VersionInfoKeys Name="FileDescription">Thrift Tutorial</VersionInfoKeys>
-						<VersionInfoKeys Name="FileVersion">0.16.0.0</VersionInfoKeys>
+						<VersionInfoKeys Name="FileVersion">0.17.0.0</VersionInfoKeys>
 						<VersionInfoKeys Name="InternalName">DelphiClient</VersionInfoKeys>
 						<VersionInfoKeys Name="LegalCopyright">Copyright © 2012 The Apache Software Foundation</VersionInfoKeys>
 						<VersionInfoKeys Name="LegalTrademarks"/>
 						<VersionInfoKeys Name="OriginalFilename">DelphiClient.exe</VersionInfoKeys>
 						<VersionInfoKeys Name="ProductName">Thrift</VersionInfoKeys>
-						<VersionInfoKeys Name="ProductVersion">0.16.0.0</VersionInfoKeys>
+						<VersionInfoKeys Name="ProductVersion">0.17.0.0</VersionInfoKeys>
 						<VersionInfoKeys Name="Comments"/>
 					</VersionInfoKeys>
 					<Source>
diff --git a/tutorial/delphi/DelphiServer/DelphiServer.dproj b/tutorial/delphi/DelphiServer/DelphiServer.dproj
index 82a2cee..31e8fd8 100644
--- a/tutorial/delphi/DelphiServer/DelphiServer.dproj
+++ b/tutorial/delphi/DelphiServer/DelphiServer.dproj
@@ -121,13 +121,13 @@
 					<VersionInfoKeys>
 						<VersionInfoKeys Name="CompanyName"/>
 						<VersionInfoKeys Name="FileDescription">Thrift Tutorial</VersionInfoKeys>
-						<VersionInfoKeys Name="FileVersion">0.16.0.0</VersionInfoKeys>
+						<VersionInfoKeys Name="FileVersion">0.17.0.0</VersionInfoKeys>
 						<VersionInfoKeys Name="InternalName">DelphiServer</VersionInfoKeys>
 						<VersionInfoKeys Name="LegalCopyright">Copyright © 2012 The Apache Software Foundation</VersionInfoKeys>
 						<VersionInfoKeys Name="LegalTrademarks"/>
 						<VersionInfoKeys Name="OriginalFilename">DelphiServer.exe</VersionInfoKeys>
 						<VersionInfoKeys Name="ProductName">Thrift</VersionInfoKeys>
-						<VersionInfoKeys Name="ProductVersion">0.16.0.0</VersionInfoKeys>
+						<VersionInfoKeys Name="ProductVersion">0.17.0.0</VersionInfoKeys>
 						<VersionInfoKeys Name="Comments"/>
 					</VersionInfoKeys>
 					<Source>
diff --git a/tutorial/netstd/Client/Client.csproj b/tutorial/netstd/Client/Client.csproj
index cf01951..158e592 100644
--- a/tutorial/netstd/Client/Client.csproj
+++ b/tutorial/netstd/Client/Client.csproj
@@ -24,7 +24,7 @@
     <AssemblyName>Client</AssemblyName>
     <PackageId>Client</PackageId>
     <OutputType>Exe</OutputType>
-    <Version>0.16.0.0</Version>
+    <Version>0.17.0.0</Version>
     <GenerateAssemblyConfigurationAttribute>false</GenerateAssemblyConfigurationAttribute>
     <GenerateAssemblyCompanyAttribute>false</GenerateAssemblyCompanyAttribute>
     <GenerateAssemblyProductAttribute>false</GenerateAssemblyProductAttribute>
diff --git a/tutorial/netstd/Interfaces/Interfaces.csproj b/tutorial/netstd/Interfaces/Interfaces.csproj
index a288745..d04b243 100644
--- a/tutorial/netstd/Interfaces/Interfaces.csproj
+++ b/tutorial/netstd/Interfaces/Interfaces.csproj
@@ -22,7 +22,7 @@
     <TargetFramework>net6.0</TargetFramework>
     <AssemblyName>Interfaces</AssemblyName>
     <PackageId>Interfaces</PackageId>
-    <Version>0.16.0.0</Version>
+    <Version>0.17.0.0</Version>
     <GenerateAssemblyConfigurationAttribute>false</GenerateAssemblyConfigurationAttribute>
     <GenerateAssemblyCompanyAttribute>false</GenerateAssemblyCompanyAttribute>
     <GenerateAssemblyProductAttribute>false</GenerateAssemblyProductAttribute>
@@ -41,8 +41,8 @@
     <Exec Condition="'$(OS)' == 'Windows_NT'" Command="where thrift" ConsoleToMSBuild="true">
       <Output TaskParameter="ConsoleOutput" PropertyName="PathToThrift" />
     </Exec>
-    <Exec Condition="Exists('$(PathToThrift)')" Command="$(PathToThrift) -out $(ProjectDir) -gen netstd:wcf,union,serial -r ./../../tutorial.thrift" />
-    <Exec Condition="Exists('thrift')" Command="thrift -out $(ProjectDir) -gen netstd:wcf,union,serial -r ./../../tutorial.thrift" />
-    <Exec Condition="Exists('./../../../compiler/cpp/thrift')" Command="./../../../compiler/cpp/thrift -out $(ProjectDir) -gen netstd:wcf,union,serial -r ./../../tutorial.thrift" />
+    <Exec Condition="Exists('$(PathToThrift)')" Command="$(PathToThrift) -out $(ProjectDir) -gen netstd:wcf,union,serial,net6 -r ./../../tutorial.thrift" />
+    <Exec Condition="Exists('thrift')" Command="thrift -out $(ProjectDir) -gen netstd:wcf,union,serial,net6 -r ./../../tutorial.thrift" />
+    <Exec Condition="Exists('./../../../compiler/cpp/thrift')" Command="./../../../compiler/cpp/thrift -out $(ProjectDir) -gen netstd:wcf,union,serial,net6 -r ./../../tutorial.thrift" />
   </Target>
 </Project>
diff --git a/tutorial/netstd/Server/Program.cs b/tutorial/netstd/Server/Program.cs
index d9c9dbf..29b21d0 100644
--- a/tutorial/netstd/Server/Program.cs
+++ b/tutorial/netstd/Server/Program.cs
@@ -131,7 +131,7 @@
             if (selectedTransport == Transport.Http)
             {
                 if (multiplex)
-                    throw new Exception("This tutorial semple code does not yet allow multiplex over http (although Thrift itself of course does)");
+                    throw new Exception("This tutorial sample code does not yet allow multiplex over http (although Thrift itself of course does)");
                 new HttpServerSample().Run(cancellationToken);
             }
             else
diff --git a/tutorial/netstd/Server/Server.csproj b/tutorial/netstd/Server/Server.csproj
index 6bee63f..cf11a75 100644
--- a/tutorial/netstd/Server/Server.csproj
+++ b/tutorial/netstd/Server/Server.csproj
@@ -24,7 +24,7 @@
     <AssemblyName>Server</AssemblyName>
     <PackageId>Server</PackageId>
     <OutputType>Exe</OutputType>
-    <Version>0.16.0.0</Version>
+    <Version>0.17.0.0</Version>
     <GenerateAssemblyConfigurationAttribute>false</GenerateAssemblyConfigurationAttribute>
     <GenerateAssemblyCompanyAttribute>false</GenerateAssemblyCompanyAttribute>
     <GenerateAssemblyProductAttribute>false</GenerateAssemblyProductAttribute>
diff --git a/tutorial/ocaml/_oasis b/tutorial/ocaml/_oasis
index 5a98ccd..9e211fc 100644
--- a/tutorial/ocaml/_oasis
+++ b/tutorial/ocaml/_oasis
@@ -1,5 +1,5 @@
 Name: tutorial
-Version: 0.16.0
+Version: 0.17.0
 OASISFormat: 0.3
 Synopsis: OCaml Tutorial example
 Authors: Apache Thrift Developers <dev@thrift.apache.org>