3.7.2 End of Support for Legacy Outlook

Summary

Before October 2029, users will need to either switch from Legacy Outlook to New Outlook or switch to another mail client (such as Apple Mail). Currently, SpamSieve can indirectly filter mail in New Outlook. We hope to be able to offer direct integration in the future.

Some customers with Exchange accounts will need to switch sooner, by October 2026. Apple Mail is also (temporarily) losing support for Exchange accounts. Until that’s restored, we think the best option for Exchange users is the MailMaven e-mail client, as it supports both modern Exchange and SpamSieve.

Legacy Outlook vs. New Outlook

SpamSieve has worked with Microsoft Outlook and its predecessors since its inception in 2002. This was possible because of their strong support for AppleScript. This macOS technology let SpamSieve access the contents of your e-mail messages (so it could determine whether they were spam), see which messages you had selected for training, and tell Outlook to move the spam messages to the Junk Email folder.

In October 2020, Microsoft introduced a new version of Outlook built on Web technologies. Many popular features were missing, including AppleScript and rules. Microsoft said that it would continue to support both the current and new versions of Outlook, as separate modes within the same app, while it worked on bringing the new version up to feature parity. Initially, there was a switch to let you opt in to preview the “New Look” version. In recent years, the new version was the default and there was a switch to go back to “Legacy Outlook.” Running in legacy mode has been required for compatibility with SpamSieve because the new mode has not yet restored AppleScript support.

AppleScript Support in New Outlook

Starting in 2020, Microsoft had consistently said that it would bring AppleScript support to New Outlook. We had planned to update SpamSieve as necessary to work with the new AppleScript support when it arrived. On August 12, 2026, Microsoft announced a change in plans:

We have decided not to move forward with this feature. We apologize for the inconvenience.

With no AppleScript support and no other means of automating Outlook, it is not possible for SpamSieve to directly integrate with New Outlook. We hope that some other method of integration will be possible in the future, e.g. if Microsoft adds support for plug-ins or a different kind of scripting.

Ending Support for Legacy Outlook

Microsoft has announced that, as of October 2026, it will be ending support for Legacy Outlook. This means that “technical support will be provided on a best-effort basis” unless you have a business/enterprise license for Exchange SE (On-Premises) or have purchased purchased Outlook LTSC (Office Long Term Service Channel). However, Legacy Outlook will still be available for download and still receive security updates through October 9, 2029. If you have an active Outlook license, you’ll still be able to use it with IMAP and POP mail accounts, and it will still directly integrate with SpamSieve.

We believe, but cannot guarantee, that existing downloads of Outlook (as well as older versions of Outlook such as 14.x and 15.x from before Outlook was subscription-based) will continue to work beyond 2029. However, they will not receive updates for security or new macOS versions.

Ending Support for Exchange Web Services (EWS)

Separately, Microsoft is retiring the EWS service on October 1, 2026. This means that customers with Exchange accounts will not be able to access them from Legacy Outlook unless they have a business/enterprise license for Exchange SE (On-Premises) or have purchased purchased Outlook LTSC (Office Long Term Service Channel). Apple Mail will also be losing access to Exchange accounts until Apple implements Microsoft’s newer Graph API. If you use Exchange, you can switch to the MailMaven e-mail client, as it supports the new Graph API for Exchange and has built-in support for SpamSieve. Or you could set Outlook to connect to your mail account using IMAP (if you hosting provider supports that) or switch to a different provider.

What Can I Do?

Continue Using Legacy Outlook

If you’re using Legacy Outlook with IMAP or POP accounts, that should continue working through October 9, 2029. Additional options may become available before then.

Switch to New Outlook and Filter Mail Using Apple Mail

You can still use SpamSieve to filter your Outlook e-mail even though SpamSieve cannot directly communicate with New Outlook. All Macs include Apple’s Mail app, and it works great with SpamSieve. If you add your mail accounts to Apple Mail and set up SpamSieve for Apple Mail, SpamSieve and Mail will filter your inbox, and the spam messages will automatically be removed from your Outlook inbox, too.

This works for IMAP and Exchange accounts, but not for POP accounts.
You’ll need to set Mail as a login item or remember to launch Mail when you restart your Mac.
You can hide Mail or run it without any windows open so that the filtering happens invisibly in the background.
You do not have to retrain SpamSieve from scratch; it will keep using the same training data from when you were using it with Outlook.
If you need to correct any filtering mistakes you can train SpamSieve directly from Outlook by moving messages into the special TrainSpam or TrainGood mailbox. To do this, first make sure that Train messages in TrainSpam and TrainGood is selected in the Settings ‣ Apple Mail ‣ Training window. There’s more information about how this works in the Drone Setup and Remote Training section of the manual.

Switch to Another Mail Client

There are a variety of native Mac mail clients that work with SpamSieve and remain in active development: Apple Mail, Airmail, GyazMail, MailMate, MailMaven.

Send Feedback to Microsoft

We hope that Microsoft will change its mind about AppleScript or add another plug-in or extension mechanism. You can choose Give Feedback from the Help menu in Outlook to ask Microsoft to prioritize this (or other features like rules that you miss).