Apple has just released updates for macOS. High Sierra has a full update to version 10.13.3, which is claimed to fix SMB problems in the previous version, and patches several significant vulnerabilities. For Sierra and El Capitan users, this is a large (841 MB or so for Sierra) security update which includes mitigation for the Meltdown CPU vulnerability. There is also a further update to Safari, bringing it to version 11.0.3.

On my iMac17,1, the Sierra security update took less than ten minutes to install. There were two cycles of white-on-black progress bar followed by a chimed restart. After the second restart, there was a nearly-complete progress bar which was slow to finish, then it came up with the normal login screen.

As far as Sierra goes, this is effectively 10.12.7, with a lot of important updates, including the APFS file system.

Hopefully these will address compatibility with High Sierra’s APFS, although the version number given is 0.3, which remains well below the current release in High Sierra. The update includes new versions of apfs_util, apfs_invert, apfs_snapshot, fsck_apfs, hfs_convert, mount_apfs, newfs_apfs, and slurpAPFSMeta, together with a new apfs.kext. Most other kernel extensions have been updated, as has WebServer, and many fonts.

The Sierra security update on this iMac brought with it at least an EFI firmware update, and the system version is now shown as 10.12.6 (16G1212), with a kernel version of 16.7.0.

The High Sierra update is a tad under 2 GB in size. Installation seems fairly straightforward, with one chimed restart on my ancient MacBook Air, but a similar sequence of progress bars. My MacBook Air did not undergo a firmware update, as far as I can see at present.

According to Apple, this brings two significant updates to High Sierra: it fixes a problem in Messages, and fixes the severe freezing problems which have been occurring when using SMB in 10.13.2. Although the latter in particular was essential, they and less than a couple of dozen security fixes don’t explain away nearly 2 GB of install.

From a quick look through, 10.13.3 updates the App Store, Automator, Calendar, Contacts, Dictionary, FaceTime, FontBook, Mail, Maps, Messages, Notes, Photos, Console, Disk Utility, System Information, VoiceOver Utility, the iLife Media Browser, most of the tools in /System/Library/CoreServices, most kernel extensions, APFS is brought up to version 748.41.3 from 748.31.8 in 10.13.2, most frameworks and private frameworks, and more too. If you want a look now at a full listing of what was installed on your Mac during the upgrade, my free app SystHist lists every single file; it is available from Downloads above.

Security fixes confirmed by Apple include: vulnerability to crafted audio files (all), Meltdown mitigation (10.12.6, 10.11.6 only) which appears similar to that released in macOS 10.13.2 in December, several other kernel bugs (mainly 10.13.2), and a Wi-Fi vulnerability affecting all versions. For Sierra’s 841 MB of update, Apple only lists nine fixed vulnerabilities, which gives a good idea of how much of the ‘security update’ is not directly related to security, but general bug-fixes.

The El Capitan security update is almost as hefty as that for Sierra, suggesting that Apple has taken the opportunity to make a number of more general bug fixes here too, which is very welcome.

For those still using Sierra, this is the most encouraging update since 10.12.4, I think: maybe Apple has been listening after all.

As usual, the updates are available from the App Store. Standalone updates are available from:

• here for High Sierra 10.13.3 for most models
• here for High Sierra 10.13.3 for the iMac Pro
• here for the Combo update for High Sierra 10.13.3
• here for Sierra Security Update 2018-001
• here for El Capitan Security Update 2018-001

There are also updates to iOS 11.2.5, watchOS, and tvOS, which are all much smaller, thankfully.