New Post: This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.

Hi Nils,

When you say "the latest version", do you mean the v5.1 beta? If not, that is the only supported path for BizTalk 2013. The correct version of GacUtil.exe is installed during the Deployment Framework installation when it detects which version of BizTalk is installed on the machine. I'm assuming that you installed the Deployment Framework after installing BizTalk 2013? Another possibility -- are you just building this all locally, or on a build server? Sometimes people upgrade BTDF on the developer side but forget to upgrade the build server.

Thanks,
Tom