After you have installed Feature Pack 2 (FP2) Cumulative Update 3 (CU3), FP2 CU4 or FP3 CU5 on Microsoft BizTalk Server 2016, you try to open or create a BizTalk project in Microsoft Visual Studio. In this situation, you will get an error message due to the unsigned Assembly BizTalkApplication.dll in BizTalkApplication.vsix:
The 'PublishCommandPackage' package did not load correctly.