diff --git a/src/OpenTK.GLWidget/OpenTK.GLWidget.csproj b/src/OpenTK.GLWidget/OpenTK.GLWidget.csproj
index fa3ea640..5ed427a5 100644
--- a/src/OpenTK.GLWidget/OpenTK.GLWidget.csproj
+++ b/src/OpenTK.GLWidget/OpenTK.GLWidget.csproj
@@ -41,7 +41,7 @@
     <BootstrapperEnabled>true</BootstrapperEnabled>
     <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
     <TargetFrameworkProfile />
-    <LangVersion>7</LangVersion>
+    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>