Update 6/13/2025: Please see our new blog post for updated timelines of releases as well as additional details on how to get from current versions of Exchange Server to Exchange Server SE: Upgrading ...
Updated Jun 13, 2025
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Blog Post
Hi Microsoft,
About operating system in-place upgrades with the upcoming Exchange Server Subscription Edition (SE).
Specifically, if we in-place upgrade to Exchange Server SE on a Windows Server 2022 from Exchange Server 2019 CU15, will it then be supported to perform an in-place upgrade of the operating system to Windows Server 2025 at a later stage?
I understand that OS in-place upgrades are currently not supported for Exchange Servers. Will this limitation be reconsidered or addressed with the introduction of Exchange Server SE?
Apologies if I'm misunderstanding, but you seem to be saying that you understand that OS in-place upgrades are not supported for Exchange Servers, but then ask if you can upgrade to Windows 2025 on your Exchange Server SE from Windows 2022.
I believe the answer remains: No, in place upgrades of the underlying OS on which Exchange running is not supported. Microsoft ( Nino_Bilic​ and/or ScottSchnoll​ ) has advised they are aware of the myriad requests to support it however.
+1 for your request though 🙂
Kind of :) Asking if OS in-place upgrades are something that may be a possibility in the future.
But I got the answer I was looking for.
I believe it's the last piece for many of us for a smooth(er) Exchange lifecycle. Given Exchange SE will be subscription/cloud supported, it seems to me (read, "I assume," so trust as far as you can throw) it will be the last version of Exchange ever for on-prem, updated in perpetuity. (Microsoft could choose to discontinue Exchange SE on-prem at some point; but given some customer industry mandated requirements to keep email data sovereignty local, I also assume this is less likely.)
As such, on a physical server, one would need to replace hardware naturally as it ages out so migrating Exchange (from metal to metal) is still something that would need to happen periodically (and at that point presumably the replacement Exchange server has the newer OS).
However, in a pure-virtual environment (perhaps this is why Nino_Bilic​ mentioned physical vs. virtual servers), technically, the Exchange SE server (as a virtual guest) could be maintained, upgraded, and migrated to other physical host hardware, all without needing a metal-to-metal migration. In this scenario (which I am in) ideally, one could:
- Keep Exchange SE perpetually up to date with CU/SU/HUs
- Upgrade the underlying OS on the Exchange Server virtual guest when necessary (OS goes EOL) if it were supported.
- Migrate the Exchange Server virtual guest to an alternate physical host when necessary
The abstracted virtual layer presents unique opportunities for an uninterrupted lifecycle for Exchange Server (but only if upgrading the underlying OS becomes supported).
- Nino_Bilic
Microsoft
That ^ is correct. As of now, Exchange does not support major OS upgrades "under Exchange" rather - this would require a server rebuild. Realistically this is not an issue for many customers if they are running on hardware but in a situation where Exchange is virtualized - then it becomes a bit more interesting.
Anyway - we do not support this at this time, but it is a request we heard of, indeed.
