Troubleshooting BizTalk Server Migration
This section provides a centralized location for information about common problems encountered while migrating BizTalk applications from BizTalk Server 2006 R2 or BizTalk Server 2009 to BizTalk Server 2013 R2.
While upgrading from BizTalk Server 2006 R2 or BizTalk Server 2009 to BizTalk Server 2013 R2, some custom applications might not work.
All the BizTalk managed code components run on CLR 4.0. As these components are compiled against .NET Framework 4.5, they need a config file to run in CLR 4.0.