diff --git a/src/MicroStationTagExplorer/MicroStationTagExplorer.csproj b/src/MicroStationTagExplorer/MicroStationTagExplorer.csproj
index 6a8431b..b085fc7 100644
--- a/src/MicroStationTagExplorer/MicroStationTagExplorer.csproj
+++ b/src/MicroStationTagExplorer/MicroStationTagExplorer.csproj
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>