Outlook Classic Support Until At Least 2029

The New Outlook for Windows Won’t Replace Outlook Classic for Another Five Years

A March 7 Technical Community post laid out Microsoft’s plan to bring the new Outlook for Windows client (aka, Outlook Monarch, Figure 1) from its current state to general availability for commercial customers and eventually to replace the Outlook Classic (Win32) client.

The bottom line is that there’s lots of twists and turns to play out before the replacement of Outlook classic. Microsoft says that they will “continue to honor published support timelines for existing version of classic Outlook for Windows until at least 2029.” Whether Microsoft means January 2029 or December 2029 is immaterial at this point. The exact timeframe will be determined based on development progress between now and then.

Monarch Used by Consumer Clients

Monarch is already in use by consumer users where it replaces the old Windows Mail and Calendar clients. Although Monarch is a superior client, its introduction has been marked by a great deal of adverse comments about the way Microsoft uploads email data to its servers (here’s one example).

The problem is that Outlook supports connects to servers via obsolete email protocols like IMAP4 and POP3 but wants to deliver advanced features that aren’t available in the old protocols. The solution is to synchronize email from the servers to Microsoft’s cloud environment to process the email data to support functionality like the focused inbox. Outlook mobile uses the same mechanism, but Monarch’s usage seems to be considered different. It’s odd, but there you are.

Bringing the New Outlook for Windows to Commercial Customers

Commercial customers are different. They tend to send and receive higher volumes of email and use different features than consumers do. For instance, consumers don’t use the Teams Meeting add-in to schedule online meetings, nor do they protect email with sensitivity labels or keep messages in archive mailboxes, including expandable archives. And customer organizations and ISVs have created a bunch of add-ins for Outlook over the years, many of which are still in active use.

In their article, Microsoft points to the transition of Outlook for Mac users to the new version of that client and say that they plan to take the same approach with the new Outlook for Windows. The only problem is that the user base for Outlook Classic is much larger and more diverse in terms of add-ons than Outlook for Mac is. The complexities involved in moving users off Outlook Classic might just be more difficult than implied by Microsoft’s confident stance.

In any case, Microsoft’s plan unfolds over three phases (Figure 2):

• Opt-in. We’re currently in this phase. General availability for the new Outlook will happen during the phase.
• Opt-out. The new Outlook client becomes the default and users must opt-out to continue using Outlook Classic.
• Cutover. New deployments will only use the new Outlook and the ability to switch back to Outlook Classic disappears. Eventually, Microsoft will cease support for Outlook Classic and might block connections at this point.

Monarch Still Lacks Features

During the development process, Microsoft has added many features to satisfy customers such as support for personal email accounts. However, some major pieces of functionality that are important to corporate customers are still missing, the most notable being the lack of support for PST files and the ability to work offline (a true strength of Outlook Classic since the introduce of drizzle-mode synchronization in Outlook 2003).

Without these features, Monarch resembles a slightly prettier and better client than the standard OWA for Exchange Online. And if people have chosen to use Outlook Classic instead of OWA, they’re not going to be tempted to use the new client until it supports all the features that they’ve come to depend on in Outlook Classic. Further difficulties arise in the need to convert COM or VSTO-based add-ins, which aren’t supported by the new client, to the new add-in model.

The Need for Balance

It’s good that Microsoft has laid out the availability timeline for Outlook over the next five years. It’s in Microsoft’s interests to get to the new Outlook (reduced engineering expenses and less complexity in the Outlook client family) but they can’t make customers (or rather, too many customers) unhappy through the transition. Achieving their goal will force Microsoft to walk a tightrope. Let’s hope that they don’t inconvenience too many people along the way. I think Outlook Classic will make it past 2029. The only question is “how long?”

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