diff --git a/contrib/zeromq/csharp/AssemblyInfo.cs b/contrib/zeromq/csharp/AssemblyInfo.cs
index 8d7ed39..7f91c33 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("0.20.0.0")]
+[assembly: AssemblyVersion("0.21.0.0")]
 
 // The following attributes are used to specify the signing key for the assembly,
 // if desired. See the Mono documentation for more information about signing.