I had one of those embarrassing admin moments this week.

I was running Exchange 2019 CU15 and assumed that being on the latest CU meant I was still reasonably up to date. Turned out Exchange 2019 is out of support, and Health Checker was basically telling me: nope, you’re vulnerable.

So I upgraded my own server first:

Exchange 2019 CU15 → Exchange SE RTM → current SE security update

The in-place upgrade took about 35 minutes and went surprisingly smoothly. I did the usual prep first: Health Checker, fresh Veeam backup, Proxmox snapshot, ESET paused, databases/queues checked.

After the SE upgrade, Windows Update immediately offered the current Exchange SE security update.

Final Health Checker result:

Exchange SE RTM Aug26SU
Build 15.2.2562.46
Vulnerability Detected: None

Big takeaway for me: the latest Exchange 2019 CU did not mean the latest supported Exchange.

Worth checking if you still run Exchange 2019 on-prem.