Released: February 2023 Exchange Server Security Updates

null-null this is expected as we reverted the change to update the serialNumber with the February 2023 Security Update. The serialNumber will remain the same (e.g., if you had the January 2023 SU installed before, it'll then show the build number of the January 2023 SU). The whenChanged attribute will be updated if at least one attribute of the server object (msExchExchangeServer class) is touched by the installer. 

Version error when you install Exchange Server in RecoverServer mode – going forward, February 2023 and newer SUs will not cause this issue (but modifications made by the January 2023 SU might still require manual action during a server recovery operation, so the steps outlined in the article might still apply with later SUs installed)

As Nino_Bilic said: the version issue is a cosmetic one and it shouldn't affect your server. The only time this might be a problem is if you need to run an Exchange Server /recover setup. 

You can revert the serialNumber back to reflect the build from the CU that you're running by following the steps outlined here:

Version error when you install Exchange Server in RecoverServer mode - Exchange | Microsoft Learn

chrlie I wasn't able to reproduce the behavior. One more question: Did you reboot the machine after running the Set-ADObject command before installing the February 2023 SU? This would explain the behavior as to logic to update the serialNumber attribute was executed by the AD Topology Service and everytime the service is started. This was changed with the February 2023 SU as the logic was removed.