ManifestUpdateFile.targets

<Project xmlns='http://schemas.microsoft.com/developer/msbuild/2003' ToolsVersion="12.0">

  <UsingTask TaskName="UpdateManifest" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v12.0.dll">
    <ParameterGroup>
      <ManifestFile ParameterType="System.String" Required="true" />
      <BuildVersion ParameterType="System.String" Required="true" />
    </ParameterGroup>
    <Task>
      <Reference Include="System.Xml"/>
      <Using Namespace="System.Xml"/>
      <Using Namespace="System.IO"/>
      <Code Type="Fragment" Language="cs"><![CDATA[
string contents = "";
using(StreamReader reader = new StreamReader(ManifestFile))
{
  contents=reader.ReadToEnd();
}
string minVersion = "";
string maxVersion = "";
if(BuildVersion.Equals("v2015_Debug") || BuildVersion.Equals("v2015_Release"))
{
  minVersion = "12.0";
  maxVersion = "12.9";
}
else if(BuildVersion.Equals("v2014_Debug") || BuildVersion.Equals("v2014_Release"))
{
  minVersion = "11.0";
  maxVersion = "11.9";
}
else if(BuildVersion.Equals("v2011_Debug") || BuildVersion.Equals("v2011_Release"))
{
  minVersion = "9.0";
  maxVersion = "10.9";
}

XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(contents);
xmlDoc["PluginPackage"]["RequiredProduct"].SetAttribute("maxversion", maxVersion);
xmlDoc["PluginPackage"]["RequiredProduct"].SetAttribute("minversion", minVersion);
XmlTextWriter wr = new XmlTextWriter(ManifestFile, Encoding.UTF8);
wr.Formatting = Formatting.Indented; 
xmlDoc.Save(wr);
wr.Close();
]]></Code>
    </Task>
  </UsingTask>

</Project>