Is there a list of “breaking changes” (i.e. what type of changes to a workflow with break existing instances)

Question

Is there a list somewhere that lays out all of the types of changes that can be made to an existing workflow service that would prevent existing instances of the original workflow from being re-loaded? For example, I recently made a small change to a custom activity (changed a condition in an "if" statement) and all existing workflow instances still load as normal. Now, in the past, I had removed a property on an object that the workflow uses, and when I tried to re-load a persisted workflow instance, it blew up on me.

Does such a list exist? Thanks!

Answer 1

As far as I am aware there isn't a list like that. You really should consider all changes as breaking. If you test thoroughly you will find a few exceptions but these will be mostly changing a single VB expression.

Answer 2

There is no such a list. As far as I am concerned, you can change VB expressions always editing the .xamlx in a text editor. I say that, because in my case, sometimes the graphical editor (VS2010) changed the ids of the activities without introducing new activities (be carefull with this).

You can also change the whole internal code (not the inputs/outputs parameters) in code activities (.xaml). Because of that, it would be a good idea to put all the "high changeable" logic into code activities in order to be able to modify this logic avoiding problems with existing WF instances.