SpamSieve Public Beta and macOS 14 Sonoma

SpamSieve 2.9.52 is incompatible with Apple Mail on the beta version of macOS 14. Although Apple has not made a formal announcement, it appears that Sonoma removes support for Mail plug-ins, perhaps because the mechanism was being used to sideload iOS apps.

With macOS Monterey, Apple announced Mail Extensions as the replacement for Mail plug-ins. Extensions have great potential to make SpamSieve easier to install and more compatible with future OS versions. I’ve been working with the API since day one and filing bugs about areas that didn’t work properly. Some of these have been fixed, but some bugs and limitations remain in macOS 14 Developer Beta 1. I will work around them as best I can, but to get the smoothest possible user experience it would help if others could file feedbacks with Apple about these two issues so that it knows to prioritize them:

  • MEMessageActionHandler is not invoked for messages that were moved by a rule (FB10590648). This effectively means that Mail Extensions do not have access to filter messages that had already been filed into a mailbox by a rule that you created. They only see the messages that remain in the inbox. For Mail’s built-in junk filter, there’s a checkbox titled Filter junk mail before applying my rules. Something like this probably makes sense for extensions, too.

  • MEMessageActionHandler only receives partial message data for messages with attachments (FB10590158). SpamSieve has historically worked with the entire raw message data. For example, some spam messages contain a very small amount of text but also an image, and SpamSieve can analyze the image’s content to help determine whether the message is spam. It also looks at the text content and formatting of attached documents. If this data is not available to Mail Extensions, filtering will be somewhat less accurate, and SpamSieve’s backup feature will be unable to save a full copy of the message.

Switching SpamSieve to use a Mail Extension requires major changes throughout the app, so this will be part of a major upgrade (version 3.0) rather than a maintenance update (like with previous OS updates). This new version is currently in development, and I plan to roll it out to a private beta group soon and eventually to a public beta this summer, with the public release before macOS 14 ships in the fall. Anyone who purchases SpamSieve 2.x during this period will get a free upgrade to version 3, and there will also be other upgrade discounts available. (To be clear, SpamSieve is not switching to a subscription model.) SpamSieve 3 will continue to support Mail plug-ins for those who prefer the feature set they offer, as well as to maintain compatibility with earlier versions of macOS that do not support Mail Extensions.

Thanks for your patience as I finish up the development of the SpamSieve Mail Extension and the rest of the app. When there’s updated information about support for macOS 14 I will post it here. You can set the forum to watch this topic (at the bottom of the page), subscribe to its RSS feed, or click here to configure your copy of SpamSieve 2 to notify you when the public beta is available. In the meantime, please file feedbacks with Apple.

Update (2023-08-22): The public beta version is now available. Please send any feedback directly to (not to the forum).


thank you!

Thank you as well Michael. I’ll file feedback. Best - Myles T.

Thank you! I would welcome participating in the private beta if you are still looking for people

I would also like to participate in the private beta, thank you

Configured SS to receive beta updates so I assume I’m enrolled but if not, of course I’d love to participate. Thanks for your great work Michael.

Thanks for the detailed information. Also would love to be part of the private beta!

I’m running macOS 14 developer beta. I can run your beta also.

NDA ok if you wish

Please add me to the list of beta testers.

Ready for the beta. Thanks, Michael.

Please add me to the private beta. The built-in junk filter is just not doing it for me since I downloaded the 14.0 Dev build.

Thank you for the information.
Would love to be included in the private beta.

Philippe A.

I’m also interested in trying the beta. I have Sonoma installed on my Macs already.

Very much appreciate this technical info and the assessment of its implications.

I can beta test, if you wish so

I’m currently running macOS 14 and interested in participating the private beta. Thank you!

I am also interested in beta testing, unfortunately, as the system administrator of my university i have to start beta testing very early. One more beta test makes no difference :wink:

I’m running the macOS 14 developer beta, and I’d like to be in the private beta group.