What is the difference on Dataverse Connection Setup - SDK Version 9 vs 91?

Business Central Version 20.0.37253.38055

Does anyone know what the differences are in SDK version 9 vs 91 in the “Dataverse Connection Setup” Page?

I just had a system outage after the Version 20 upgrade which took down dataverse connections on a few companies. After flipping enough options, I found that the SDK Version 9 was causing the issues. Changing to version 91 resolved.

Was getting this error:

A file for a Dataverse solution could not be found.

AL call stack:
“CDS Integration Impl.”(CodeUnit 7201).ProcessConnectionFailures line 17 - Base Application by Microsoft
“CDS Integration Impl.”(CodeUnit 7201).SignInCDSAdminUser - Base Application by Microsoft
“CDS Connection Setup Wizard”(Page 7201).“SignInAdmin - OnDrillDown”(Trigger) line 6 - Base Application by Microsoft

The fire is resolved but I would like to know what I just changed.