Accessing Microsoft Teams using organizational or personal credentials
How do you stop it from updating to 5.2.11.50 ?
I lost the page where I found that link. I was frantically trying to fix these two rooms all week. Ultimately one of the rooms I completely reimaged so it was a clean windows install. I think you can just remove the Teams room app from Settings.
Then go the the URL posted, unzip and run the .appx file. It will install version 5.1.28.0