macOS Monterey to Support All-New Mail App Extensions, Plug-Ins Will Stop Functioning in Future Release
As part of WWDC this week, Apple introduced a new MailKit framework for macOS Monterey that enables developers to create Mail app extensions that block content, perform message and composing actions, and help with security.

There will be four main categories of Mail app extensions, according to Apple:
- Compose: Extensions that provide new workflows when composing emails
- Actions: Extensions that apply custom rules to incoming emails, such as an email being color coded, moved to a separate inbox, marked as read, or flagged
- Content Blocking: Extensions that serve as WebKit content blockers for emails based on specific criteria in an email's HTML code
- Message Security: Extensions that sign, encrypt, and decrypt emails when sending and receiving mail, with signed and encrypted icons below emails
Xcode 13, available in beta, includes a template for developers looking to create Mail app extensions on the Mac. The extensions can be built into existing Mac apps and can also be distributed through the Mac App Store, according to a WWDC session about MailKit, which is available on macOS only and not iOS or iPadOS.
In the WWDC session, Apple indicated that older Mail app plug-ins will stop functioning in an unspecified future macOS release.
macOS Monterey is available now in beta for developers, with a public beta to follow in July.
Popular Stories
Apple is developing an all-new operating system codenamed "Charismatic," according to Bloomberg's Mark Gurman.
Apple smart home hub concept
This is likely Apple's long-rumored "homeOS" operating system.
In a report this week, Gurman said both Apple's rumored smart home hub in 2026 and tabletop robot in 2027 will run the new operating system. He said the software platform will blend...
Last week, Apple released and then pulled a software tool that accidentally contained identifiers for many unreleased devices and chips, according to MacRumors contributor Aaron Perris. His findings included new models of the Studio Display, Apple TV, Apple Watches, Apple Vision Pro, iPad mini, HomePod mini, and more.
Here is what was uncovered in the file, according to MacRumors contributor ...
The seventh developer beta of iOS 26 is now available. While we are now in the later stages of the iOS 26 beta cycle, there are still some changes.
Below, we outline everything new that we have found in iOS 26 beta 7 so far.
Redesigned Blood Oxygen Feature
The seventh developer betas of iOS 26 and watchOS 26 include a redesigned Blood Oxygen feature on Apple Watch Series 9, Apple Watch ...
Alleged images of the iPhone 17 Pro Max's internal design have surfaced, offering a potential look inside the device before it is announced by Apple next month.
The images were shared by the account "yeux1122" this week, in a blog post on the Korean platform Naver. The account aggregates Apple rumors and leaks, so it is likely not the original source of the images, and it is unclear if they...
Apple is expected to delay the launch of its base iPhone 18 model until spring 2027, marking a major shift in the company's long-established release cycle, according to South Korea's ETNews.
The report claims that Apple has informed some of its suppliers that the iPhone 18 will not be part of the September 2026 iPhone lineup. Instead, the company will unveil only higher-end models in the...
At least one new Apple Watch model launching next year will feature a "significant redesign," according to Taiwanese supply chain publication DigiTimes.
In a paywalled report this week, citing supply chain insiders, DigiTimes claimed that a high-end 2026 Apple Watch model will feature "exterior design" changes, including but not limited to "eight sensors arranged in a ring pattern visible...
As we wait for WWDC to kick off next Monday, Apple today announced the winners of its annual Apple Design Awards, recognizing apps and games for their innovation, ingenuity, and technical achievement.
The 2025 Apple Design Award winners are listed below, with one app and one game selected per category:
Delight and Fun - CapWords (App) and Balatro (Game)
Innovation - Play (App) and PBJ -...
Apple made a major slip Wednesday when it accidentally included hardware identifiers in software code linking to numerous unannounced products.
The leaked information provided MacRumors with concrete evidence of Apple's hardware development across multiple product categories. Here's everything that was confirmed through the code discoveries:
New HomePod mini with updated chip – New...