Even the error message being very clear of what was going on, I wasn’t expecting this behavior since it is not usual to mess around with system DLLs registrations.
After a server migration some CLR routines stopped working on the new server showing the following error.
Msg 6522, Level 16, State 1, Line 1
A .NET Framework error occurred during execution of user-defined routine or aggregate "MyUserRoutine":
System.IO.FileLoadException: Could not load file or assembly 'System.ServiceModel, Version=126.96.36.199, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. Assembly in host store has a different signature than assembly in GAC. (Exception from HRESULT: 0x80131050) See Microsoft Knowledge Base article 949080 for more information.