Group-Based Licensing (E3 → Business Premium): MutuallyExclusiveViolation – Months Unresolved

Hi Daniel, that is a painful one, especially because group-based licensing does not give you a true atomic "swap this SKU for that SKU" operation.

In practice, I would not count on group processing order to remove E3 and add Business Premium cleanly in the same evaluation cycle. If the backend sees both SKUs as conflicting at any point, `MutuallyExclusiveViolation` can block the assignment even if the end state would be valid.

For a production migration, I would test a scripted maintenance-window approach with a small pilot group: remove the old license, immediately assign the new one, then validate Exchange, Teams, OneDrive, and service-plan state. Mailboxes should not be permanently deleted instantly just because a license is briefly removed, but access can be interrupted, so the timing and rollback plan matter. If you must use inherited group licensing only, I think Microsoft support needs to confirm a supported backend path, because Entra group licensing is not really built as an atomic SKU replacement engine.