diff --git a/tutorial/dart/client/.analysis_options b/tutorial/dart/client/.analysis_options
new file mode 100644
index 0000000..a10d4c5
--- /dev/null
+++ b/tutorial/dart/client/.analysis_options
@@ -0,0 +1,2 @@
+analyzer:
+  strong-mode: true
diff --git a/tutorial/dart/client/pubspec.yaml b/tutorial/dart/client/pubspec.yaml
index 4bd3394..db64afc 100644
--- a/tutorial/dart/client/pubspec.yaml
+++ b/tutorial/dart/client/pubspec.yaml
@@ -22,7 +22,7 @@
 homepage: http://thrift.apache.org
 
 environment:
-  sdk: ^1.12.0
+  sdk: ">=1.13.0 <2.0.0"
 
 dependencies:
   browser: ^0.10.0