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
Version 14.0
Blog Post
Nino_Bilic
Microsoft
MicrosoftTo help clarify “unsupported” as far as Exchange 2026 and October 2025:
- No more security updates
- No support tickets / requests for fixes / bug reports
- We typically support “migration scenarios” for older versions for a while
We have long stated that Hybrid customers should be running the “latest CU”. While right now I do not expect anything explicitly to break for an Exchange 2016 hybrid customer after October 2025 passes, there could be something. Something security related? A service change?
Your Exchange Server 2026 will continue working after October 2025 but note that in Exchange Server SU CU1, we plan to remove coexistence with all unsupported versions (which Exchange Server 2016 will be at that point).
So yes – the best path forward is to not wait; do your hardware buildouts now. Decide on the Windows OS you want to use (2022 or wait a little longer for 2025) and migrate to Exchange Server 2019 now. Then, when Exchange SE comes, you can in-place to SE with that “lightweight” CU-like upgrade. This will not be a “legacy” upgrade.