When Does Classic Outlook Support End? Dates and Stages

When does classic Outlook support end?#

Classic Outlook support does not end on a published date. As of July 2026 Microsoft has not announced one. Existing installations of classic Outlook through perpetual and subscription licensing are supported until at least 2029, and the move to new Outlook runs in three stages with at least twelve months of notice before each one.

That is the whole answer, and it contradicts a claim you have probably already read: that classic Outlook dies in 2026. It does not. The 2026 dates in circulation are real dates attached to other things, which is exactly why the error keeps spreading.

The rest of this page explains the staged model so you can predict what happens next instead of re-checking the news every quarter. It also separates the handful of items that genuinely have dates from the ones that do not.

Support ending and being switched by default are not the same thing#

Almost every wrong headline on this topic comes from collapsing two separate events into one. They have different mechanics, different timelines and different consequences, and a plan that confuses them prepares for the wrong thing.

Support ending means Microsoft stops shipping fixes and security updates. That is a lifecycle event, it is published years ahead on Microsoft's lifecycle pages, and it lands on a fixed calendar date.

Being switched by default means the toggle flips and new Outlook opens instead of classic Outlook. Support has not ended. The classic client is still installed, still patched, and during the opt-out stage users can switch straight back.

• Support ends: no more updates or fixes. Published in advance on Microsoft's lifecycle pages with a fixed date.
• Default changes (opt out): new Outlook opens first, classic Outlook still works, and users can revert.
• Cutover: users can no longer switch back and new Microsoft 365 deployments ship new Outlook. Still not the same as support ending.

Microsoft's three stages, in one table#

Microsoft describes the migration as three progressive stages: opt in, opt out and cutover. Knowing which stage applies to your licence tells you what can happen to your users this year without you doing anything at all.

The column that matters most is the last one. Once you know each stage carries at least twelve months of notice, you stop needing a date and start needing to know whether the notice has been given.

What the twelve-month notice actually promises#

Microsoft's commitment is specific. After general availability, it uses existing channels to give a notice of disruptive change twelve months before moving to the opt-out and cutover stages in production rings.

That phrasing carries two limits worth reading closely. The notice is tied to production rings, so preview and targeted-release users can meet a change earlier. And at least is a floor rather than a schedule — Microsoft has already used more than twelve months once.

For planning, this turns an unknowable date into a rolling twelve-month horizon. If no notice has landed in your tenant's message center, nothing disruptive can reach your production users for at least a year.

What genuinely has a date#

A small number of things in this story have real, published dates. None of them is the end of classic Outlook for Windows, and knowing the list is the fastest way to spot a bad article.

Two of these fall in October 2026, which is the single biggest source of confusion. Both are correctly scoped, and neither touches classic Outlook on Windows.

The 2029 commitment has a catch if you bought a perpetual licence#

Supported until at least 2029 is a statement about classic Outlook as an application. It is not a promise about the specific version sitting on your machine.

Perpetual Outlook releases each carry their own lifecycle date, and one of them is close. Outlook 2021 retires on 13 October 2026, under three months from now, while Outlook 2024 and Outlook LTSC 2024 both run to 9 October 2029.

That 2029 date is almost certainly where at least 2029 comes from. If you are on Outlook 2021 and reading the 2029 commitment as your own runway, you are three years out.

Why so many pages say April 2026#

The April 2026 date was not invented by bloggers. Microsoft published it: the enterprise opt-out stage was scheduled to begin in April 2026, and pages written during 2025 reported it accurately at the time.

It then moved. Microsoft's message center notice MC949965, updated on 20 February 2026, pushed the enterprise opt-out from April 2026 to 1 March 2027, citing twelve months of lead time for organisations to prepare. Applying the same twelve-month rule to the next stage puts the earliest possible cutover no sooner than March 2028.

Microsoft's public migration page carries neither date. It was revised three days after that update and still describes the current stage as opt in, which is consistent with the delay — and is why searching the public documentation for April 2026 turns up nothing.

So pages presenting April 2026 as a live deadline are quoting a superseded schedule. Pages saying support ends in 2026 were never right in the first place.

What IT should do now#

None of this requires a crash migration. It does require the six things below, most of which are cheaper to do during the opt-in stage than under a notice period.

1. 1

   Establish which licence and which mailboxes you actually have

   Check the Outlook version under File, then Office Account, and whether the mailboxes are Microsoft 365, on-premises Exchange, or a mix. New Outlook is not supported for on-premises environments, so a hybrid tenant has a hard constraint rather than a preference.

2. 2

   Read your own message center rather than the news

   The twelve-month notice arrives in the Microsoft 365 admin center under Health, then Message center. That notice is the trigger for every decision below, so assign it to a named person instead of a shared alias.

3. 3

   Set the policy that controls the default today

   Automatic migration is governed by the Manage user setting for new Outlook automatic migration policy, available through Cloud Policy, Group Policy and the NewOutlookMigrationUserSetting registry value. Setting it to 0 blocks automatic migration and stops users changing it back.

4. 4

   Inventory COM and VSTO add-ins before anything else

   New Outlook supports web add-ins only, so COM and VSTO add-ins do not carry across. This is the work with the longest lead time in the whole project and it is completely independent of any date Microsoft announces.

5. 5

   Pilot while failure is still free

   Run both clients side by side with the users who have the hardest workflows: delegates, shared mailboxes, very large mailboxes, dictation. Feedback gathered now costs nothing. The same feedback gathered after a forced default arrives as a helpdesk queue.

6. 6

   Diarise only the dates that are real for you

   Your perpetual version's retirement date, and October 2026 if anyone still runs legacy Outlook for Mac against Exchange Online. Everything else in this story is a notice, not a date.

What triggers the next decision#

You do not need to track this quarterly. Three events change the answer and everything else is noise.

• A notice of disruptive change appears in your tenant's message center. That starts a twelve-month clock to the opt-out stage reaching your production users.
• A cutover notice appears. Same twelve-month clock, but this one removes the ability to switch back, so it needs a finished add-in plan behind it.
• Your perpetual Outlook version reaches its lifecycle date. This happens on a published calendar date and has nothing to do with the migration stages.

Where to check when this changes#

Two places carry the current status, and both are Microsoft's. The stages of migration page on Microsoft Learn holds the public model, and your own message center holds anything specific to your tenant. Both are linked in the sources below.

Trade coverage is not a substitute for either, and the April 2026 story is the proof. Every status on this page is dated July 2026, and the honest instruction is to confirm it against Microsoft's page before you spend money or make a promise to a board.

Where AI Emaily fits, and where it does not#

We build AI Emaily, so the disclosure belongs here rather than buried at the end. Nothing on this page is a reason to change email clients, and a deadline that does not exist would be a bad reason to buy anything.

For completeness: AI Emaily is a separate client that connects Microsoft 365, Gmail and IMAP accounts in one place, which is one option for teams that end up rethinking the desktop client anyway. It does not replace a COM add-in and it does not move a single date above.

The short version#

As of July 2026 there is no announced end-of-support date for classic Outlook for Windows, and existing installs on perpetual and subscription licensing are supported until at least 2029.

The migration runs opt in, then opt out, then cutover, with at least twelve months of notice before each stage reaches production rings. Enterprise opt-out moved from April 2026 to March 2027 in a February 2026 message center update, which puts the earliest cutover no sooner than March 2028.

The dates that are real and near are your own perpetual version's retirement — 13 October 2026 for Outlook 2021 — and the October 2026 retirement of legacy Outlook for Mac against Exchange Online. Plan against those and against the notice in your message center, not against a headline.