Microsoft has released an update for Microsoft .NET Framework 4.0.3 and design time support update for Visual Studio 2010 SP1.
The MT(Multi-Targeting) Pack adds new reference assemblies, IntelliSense files, and other supporting files. Multi-targeting pack adds support for the new APIs that are introduced in Update 4.0.3 for Microsoft .NET Framework 4 – Runtime Update.
For more details about Targeting Pack refer to the Knowledge Base Article KB2600213.
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