Apple looks set to release its update to macOS Mojave 10.14.4 at around 1800 UTC on Monday 25 March. This will coincide with updates to its other operating systems, notably iOS 12.2 to support the new iPads which it announced yesterday and will also start shipping next week.

The unanswered question is whether Apple will release new iMacs at the same time. Its current iMacs were introduced at WWDC on 5 June 2017, and are overdue replacement with modern chipsets. If they don’t appear at this event, it’s unlikely that they will be updated until WWDC this year.

Exceptionally, Apple has already announced one of the major changes in macOS 10.14.4: Swift 5.0, which is the first release of Swift which will be directly supported by macOS rather than relying on extensive support libraries which have to be shipped inside every app which uses Swift in macOS.

The impact of this is in the longer-term; existing Swift apps should continue to run fine, but future versions of products will be able to drop the support libraries if they only run on 10.14.4 and later. It’s unclear whether that will require developers to ship two different versions in order to utilise built-in Swift support, which would appear clumsy and unlikely to gain much support until the autumn/fall with the release of macOS 10.15.

Hopefully Apple will be releasing Xcode 10.2 at the same time, with its support for Swift 5.0 and the new versions of its operating systems.

I also expect 10.14.4 to fix one of the more severe bugs in Mojave, in which the Finder hangs when you try to open or preview a Finder Alias to a folder which no longer exists. It should also close a vulnerability reported by Jeff Johnson, in which apps with hardened runtimes can access the protected folder ~/Library/Safari.

According to reports from beta testers, macOS 10.14.4 is going to bring with it EFI firmware updates for many if not all models.

Apple hasn’t released any security data updates since 21 February, so coicident with the release of macOS 10.14.4 you can expect updates to Gatekeeper at least, which will probably need to be downloaded and installed separately from the macOS update itself. Although MRT was updated on 21 February, XProtect hasn’t been updated since 11 December 2018, and should be due for update very soon too.

It looks like 25 March is going to be a busy day for downloads for anyone running macOS, iOS, watchOS and tvOS, and for Xcode users.

Postscripts:

Within a few hours of publishing this, Apple has announced new iMacs with updated chipsets, at last. Interestingly, they’re available to order now and expected to deliver next week. This is further confirmation of the imminent arrival of 10.14.4.

One surprising omission in the new iMacs, which could indicate that they are a stopgap before a definitive replacement model, is the T2 chip, which has been included in the design of every other recent Mac, even down to the basic MacBook Air and Mac mini. For those looking to a new iMac for Pro level performance, this still makes the iMac Pro worth considering carefully, because of its superior security and blazingly-fast internal storage even when FileVault is enabled.