Update (4/12/23): This feature was enabled in our worldwide and 21Vianet clouds in November 2022. All tenants in these clouds will see the changes. Rollout to our GCCH and DoD clouds has been paused ...
Updated Apr 12, 2023
Version 11.0
Blog Post
I see it took effect in our tenant, as well. Looking back at new employee accounts created, it seems to have changed around mid-day on November 2, 2022.
This tracks with Microsoft's announcement at the top about rolling out between September and December.
I still have not been able to determine whether it affects my scripts or not. The one place it is likely to is a collection of PowerShell scripts and SQL procedures to store mailbox permission and folder permission relationships in SQL Server so I can produce a report of what needs to be cleaned up on termination. That process is at (or occasionally over) the very edge of my Exchange-admin-stayed-at-a-Holiday-Inn-Express-last-night developer skills, with potential merge/join relationships between multiple fields because not every interface provides the same data about a user. Setting the Identity field randomly between the on-prem Name value and the cloud GUID doesn't help that complexity at all.