Your Exchange Server Is Out of Support: What Are the Options in 2026?

Since 14 October 2025, Microsoft no longer ships updates for Exchange Server 2016 and Exchange Server 2019, security fixes included. The server keeps running, but any vulnerability discovered after that date stays open. And a mail server is exposed by nature: it receives mail from the outside, continuously.

This is the path Microsoft recommends and the simplest in most cases. It takes the company off old technology in a single hop and opens access to larger mailboxes, security and compliance capabilities, and integration with SharePoint, OneDrive, Teams and Power BI. For an SME it is usually the cheapest option to operate over time, since there is no longer a server to maintain or replace.

Since support ended, Exchange Server Subscription Edition (SE) is the only supported on-premises version. If you run Exchange 2019, the upgrade happens in place. If you run Exchange 2016, you need a side-by-side migration onto a new server. This option still makes sense when a regulatory or business constraint requires data to stay with you, but it keeps the cost of a server, its upkeep and its backups.

The question is economic and regulatory rather than technical. Do you have a documented obligation to keep data on site? If so, Exchange SE. If not, compare total cost: licences, server, backup, administration time and incident handling on one side, subscription on the other. For an organisation with no location constraint, the calculation almost always favours the cloud.

One frequent case deserves attention: companies already on Microsoft 365 that kept an on-premises Exchange server for attribute management. That server is affected by end of support like any other. It is often overlooked, precisely because nobody uses it day to day.

Postponing on the grounds that mail still works. An unsupported server does not fail overnight: it simply becomes indefensible the day a flaw is published. And if your insurer or a client asks about system maintenance, an out-of-support component is hard to justify.