To roll back to a previous version, take the following steps.
Now you can open the project in the older version again!
Nolan
In version 5.10 of the Modeler, go to the Team menu and select Reverse Merge Changes. Pick the version(s) you would like to reverse, and let the modeler reverse merge those changes. Then save, your changes, but don't commit. Close the project and close 5.10 Modeler. Open 5.9.1 Modeler and you should be able to open the project again.
If that doesn't work, creating a new branch from a previous version as Ronald mentioned is the way to go..
Mike
There are a couple of things you can do. Most is explained here.
Or you create a new branch from the previous version and work on that branch till you got it fixed. Then you can merge the branch back to the main line.
Regards,
Ronald
This issue has been investigated and will be solved in an upcoming release. Please file a ticket if you run into this so we can offer you a workaround.
@Nolan, Ivo: you should both have received a reply from me in your ticket.