OWA Access to Online Archives Ceases on 12 May 2025

The April 17 announcement about the retirement of OWA support for cloud archives in Exchange Server dismayed some people. I received several messages to ask why Microsoft will withdraw support for OWA access to cloud archives from May 12, 2025. Some asked if this was yet another example of Microsoft releasing bad news on the cusp of a holiday weekend. Others asked why Microsoft only gave customers 25 days’ notice. And a few asked if this was the first step to retire Exchange Server (despite the imminent arrival of Exchange Server SE).

A Matter of Money

I wasn’t surprised at the news because it fits in with the current environment around Exchange Server. First, we migration to the cloud is all but finished for organizations that want to use Exchange Online. Even in hybrid organizations most mailboxes are in the cloud with a relatively small percentage still on-premises.

Organizations that wish to stay on-premises and use Exchange Server SE do so for their own reasons. Security over email is one of the primary motivations for staying on-premises, so these organizations probably generate relatively little demand for online archives (archive mailboxes hosted by Exchange Online). Coupled with a reducing set of on-premises mailboxes in hybrid environments, the overall demand for online archives cannot be high.

If Microsoft isn’t generating revenue by selling Microsoft 365 licenses to on-premises organizations to access online archives, they’ll want to reduce engineering and support costs. One way to do that is to reduce the number of clients that can access online archives when the primary mailbox is on-premises, and that’s what’s happening here.

Outlook Classic Continues

Microsoft points out that access to online archives will continue via Outlook classic. They don’t specify what version of Outlook classic is necessary, but we can assume that anyone who accesses an online archive today with Outlook classic can continue to do so after May 12, 2025.

It’s unsurprising that Microsoft chose to retire OWA access. There’s no indication that the new Outlook for Windows (aka OWA on steroids) will support Exchange Server in the future. The New Outlook is very tied to Exchange Online and moving that client to Exchange Server seems like work that Microsoft wouldn’t want to do. Simplifying the version of OWA available to Exchange Server makes that client easier to support and cheaper to maintain.

But if the new Outlook isn’t going to support Exchange Server when Outlook classic support terminates sometime in 2029, that creates the question of what clients will be available to Exchange Server customers after that time. I don’t think a simplified version of OWA will be enough for on-premises users. Unlike the new Outlook, OWA doesn’t support offline access, PSTs, and so on. Microsoft will have to do something to address the client issue for on-premises customers. It would be no surprise if Outlook classic (a version of the perpetual client, not subscription) continued after 2029. It’s a while away before we’re likely to hear about client plans for Exchange Server SE in 2029, but Outlook classic seems like a good bet (“Outlook 2030” perhaps?).

Change Happens

Change is a constant factor in the cloud and trade-offs happen between the introduction of new functionality (some is coming for Exchange Server SE) and the retirement of older underused features. Microsoft says that tenants affected by the change have received message center notification MC1053644 to let them know what’s going on. If you haven’t received the notification and think that your tenant is affected, you should contact exchonpremfeedback[AT]microsoft.com.

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