Move comes as operating system transitions to 64-bit future.
Apple is warning users that their 32-bit applications will stop working soon.
As of midnight, last night, users of MacOS 10.13.4 will see an alert whenever they launch 32-bit software for the first time when running the current MacOS version.
The alert tells users that their 32-bit software will soon stop working. When a 32-bit app is started users will see this message: “This app needs to be updated by its developer to improve compatibility.” There will also be a "learn more" link that takes them to an Apple support page with more information.
According to a support document by Apple, it began the transition to 64-bit hardware and software technology for Mac over a decade ago, and is working with developers to transition their apps to 64-bit. It added that at its last WWDC in 2017, developers were warned that macOS High Sierra “would be the last version of macOS to run 32-bit apps without compromise”.
“Starting with macOS High Sierra 10.13.4, apps that have not been updated to use 64-bit processes produce a one-time alert when opened. This gives users advance notice that they are running 32-bit software, which will not be compatible with macOS in the future,” said the support document.
While users can still use 32-bit software today with “no adverse effects”, there may be problems in the future. It added that “final transition dates have not yet been established”, but now would be a good time to see if there are64-bit versions of applications for users.
Apple said that users can check for 64-bit compatibility through the system report feature.
“From the Apple menu, choose About This Mac, then click the System Report button. From the system report, scroll down to Software, then select Applications. When you select an individual application, you will see a field titled ”64-bit (Intel)”. “Yes" indicates 64-bit; “No" indicates 32-bit,” said the document.
Apple has already completed its 64-bit transition in iOS, with similar messages displayed to iPhone and iPad users before iOS 11 was launched.