I’ve just discovered something that I really really don’t like about Microsoft CRM 4. This is that creating some custom workflow activities that are used in a Crm Workflow means they are linked together forever and ever by version numbers.
I was getting this error message:
After some investigation it turned out that it was because I had changed the version number of the assembly that contained the custom workflow activities which meant that I could no longer publish the workflows that use them. When I try I get this error message.
The answer is to manually set the version number of the dll back to what it was when the workflows were originally published which is just silly.
For a much more detailed look at this problem I found this fantastic article by Eric Bewley.