macOS Sonoma Drops Support for Legacy Mail App Plug-ins - MacRumors
Skip to Content

macOS Sonoma Drops Support for Legacy Mail App Plug-ins

by

With macOS Monterey in 2021, Apple introduced a MailKit framework that developers can use to build modern and secure extensions for the Mail app on the Mac. Extensions can be created to block content, perform message actions, improve security, and more.

General macOS Mail Feature
In turn, Apple said legacy Mail app plug-ins would stop functioning in a future macOS release, and it appears that time has now come. AltStore today said it confirmed with Apple during WWDC last week that plug-ins are not supported on macOS Sonoma, and that MailKit-based extensions are the only supported solution going forward.


While MailKit extensions are more secure, they have more limited functionality compared to legacy plug-ins, so not all plug-ins may live on as extensions.

Legacy plug-ins cannot be opened in the Mail app as of the first beta version of macOS Sonoma. The update will be released to the public later this year.

(Thanks, @aaronp613!)

Tag: Apple Mail
Related Forum: macOS Sonoma

Popular Stories

Apple Card iPhone 16 Pro Feature

Apple Card Promo to Offer Free AirPods Pro 3

Friday May 15, 2026 8:59 am PDT by
Starting as early as next week, customers who sign up for an Apple Card at Apple's retail stores in the U.S. will receive $249 cash back when they purchase AirPods Pro 3, according to Bloomberg's Mark Gurman. The promotion has yet to be officially announced by Apple, so exact terms and conditions are not available at this time. AirPods Pro 3 are priced at $249 in the U.S., so customers who...
Read Full Article • 46 comments
Apple WWDC25 iOS 26 CarPlay Light mode 250609

Six Popular iPhone Apps Now Available on CarPlay

Thursday May 14, 2026 9:10 am PDT by
Apple's CarPlay system for accessing iPhone apps on a vehicle's dashboard screen has received six popular apps in recent weeks: ChatGPT, Perplexity, Grok, Google Meet, WhatsApp, and the indie artist streaming platform Audiomack. Make sure you have the latest version of each app and they will automatically appear on CarPlay. ChatGPT Starting with iOS 26.4, CarPlay supports voice-based...
Read Full Article • 29 comments
ipad mini 7 blue

OLED iPad Mini: Release Date, Pricing, and What to Expect

Thursday May 14, 2026 5:08 am PDT by
According to the latest rumors, Apple is close to launching its next-generation iPad mini. So what should we expect from the successor to the iPad mini 7 that Apple released over a year ago? Read on to find out. Processor and Performance Apple is working on a next-generation version of the iPad mini (codename J510/J511) that features the A19 Pro chip, according to information found in code...
Read Full Article • 87 comments

Top Rated Comments

Max Webb Avatar
Max Webb
38 months ago
I didnt even know mail had plugin support full stop.
Score: 29 Votes (Like | Disagree)
redheeler Avatar
redheeler
38 months ago
Over a decade on MacOS and this is the first time I heard that the Mail app supports extensions.
Score: 26 Votes (Like | Disagree)
erikkfi Avatar
erikkfi
38 months ago

While MailKit extensions are more secure, they have more limited functionality compared to legacy plug-ins, so not all plug-ins may live on as extensions.
Apple loves doing this kind of thing -- see how they ruined Safari extensions -- and then they wonder why their native apps' usage stagnates rather than grows.
Score: 16 Votes (Like | Disagree)
D
ddauerbach
38 months ago
I'm really going to miss the really really useful SmallCubed Mailsuite suite of plugins.
Score: 11 Votes (Like | Disagree)
B
BarryTheWebdork
38 months ago

I'm really going to miss the really really useful SmallCubed Mailsuite suite of plugins.
I registered just to upvote this. SmallCubed is apparently going to release its own mail client now. So... well done, Apple.
Score: 8 Votes (Like | Disagree)
zorinlynx Avatar
zorinlynx
38 months ago
I still use Thunderbird because Apple Mail just isn't as capable. (Though I do use Apple Mail on my iPhone because the only mail client that was ever better on mobile was Sparrow and Google bought and killed that.)

People like to call Thunderbird "old" and "archaic" but E-mail hasn't changed much in 20 years. Thunderbird still does the job as well as it ever has, and they've recently started putting more development work into it so it will likely get even better moving forward.

Seriously, if you're a mail "power user", consider Thunderbird.
Score: 7 Votes (Like | Disagree)
Read All Comments