Exchange Server 2016 and 2019 reached end of support on 14 October 2025. A short, paid Extended Security Update programme followed, and its coverage ends on 31 October 2026 with no further period. The October 2026 security update is likely to be the last. After that, on-premises Exchange needs to be on Exchange Server Subscription Edition (SE) or moved to Exchange Online.
Exchange Server 2016 and 2019 end-of-life dates at a glance
| What | Date |
|---|---|
| End of support (both versions) | 14 October 2025 |
| ESU period 1 | October 2025 to April 2026 |
| ESU period 2 (Enterprise Agreement only) | 1 May to 31 October 2026 |
| ESU coverage ends | 31 October 2026 |
Exchange Server SE is the supported successor for on-premises Exchange. Exchange 2019 servers on the latest cumulative update can be upgraded in place to SE. Exchange 2016 cannot: install new SE servers alongside it, move the mailboxes, then decommission the old servers.
What end of support means for your mail servers
Exchange servers are internet-facing by design and have been a frequent target for attackers. Running an unsupported version past October 2026 means any newly found vulnerability stays open on one of the most exposed systems you have.
What to do now
- List every Exchange server, including hybrid servers kept only for management.
- Decide the destination: Exchange Server SE, Exchange Online or hybrid.
- Bring Exchange 2019 to the latest cumulative update, then upgrade in place to SE.
- For Exchange 2016, add new SE servers, move the mailboxes across and decommission the old servers properly.
- Track each server until it is upgraded or removed.
Frequently asked questions
When did Exchange Server 2016 and 2019 reach end of life?
Both reached end of support on 14 October 2025. The paid Extended Security Update programme that followed ends on 31 October 2026, and the October 2026 security update is likely to be the last.
Can I upgrade Exchange 2019 to Exchange Server SE in place?
Yes. Exchange 2019 servers on the latest cumulative update can be upgraded in place to Exchange Server Subscription Edition. Exchange 2016 cannot; it needs new servers and a mailbox move.
What are the alternatives to on-premises Exchange?
Exchange Online, or a hybrid of Exchange Server SE and Exchange Online.
Sources
Dates from Microsoft: Exchange Server 2019 lifecycle and Exchange Server 2016 lifecycle; ESU periods as reported by Messageware. Always confirm dates with the vendor before making decisions.