diff --git a/IPhreeqc.props b/IPhreeqc.props
index da54ab44..51fbcd4d 100644
--- a/IPhreeqc.props
+++ b/IPhreeqc.props
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
-    <_ProjectFileVersion>10.0.30319.1</_ProjectFileVersion>
+    <_ProjectFileVersion>10.0.40219.1</_ProjectFileVersion>
   </PropertyGroup>
   <ItemDefinitionGroup>
     <ClCompile>