Where we’re coming from: recent macOS

This is the time of year when many of us look to upgrading macOS, whether we’re going to an existing version we feel is now tried and tested, or in the autumn/fall to macOS 13 Ventura. If you’re still undecided as to which to choose, or just enjoy looking back at what we’ve been through, this article summarises their highlights and lowlights.


OS X El Capitan and macOS Sierra 10.11.x (2015-16), 10.12.x (2016-17)

These were the last two major versions before Apple introduced its new file system APFS, and remain classics for those with older models dating back to 2007-08. El Capitan is notable for its introduction of System Integrity Protection (SIP), and Sierra for Apple Pay. Far simpler and more traditional than any macOS since, they weren’t without significant flaws. Some Macs suffer complete freezes in El Capitan, and all running Time Machine backups in Sierra have to restart their Macs every few days, because of a scheduling bug which wasn’t fixed until High Sierra.


High Sierra 10.13.x (2017-18)

A combination of the traditional and the new, as the first version of macOS to support APFS, some have found it a reliable halfway house between HFS+ of the past and APFS of the future. However, this early version of the new file system doesn’t support Fusion Drives, and isn’t as reliable or full-featured as later releases. For some Macs, it’s worth avoiding, but many using older Macs still like it. It brought initial support for HEVC and HEIF/HEIC video and image encoding, but hasn’t received any security updates since 2020.


Mojave 10.14.x (2018-19)

As the last version of macOS to support 32-bit software, this was a milestone and worth preserving in a Virtual Machine, in case you ever need to fall back and use an old app which isn’t fully 64-bit compatible. It’s also the last version with a single boot volume, making it more risky in terms of vulnerabilities, but much simpler and more versatile. Its version of APFS was a big improvement on that in High Sierra, and at last supported all boot media including Fusion Drives. Because it’s reliant on Metal accelerated graphics, it requires Metal-compatible graphics hardware. It last received security updates a year ago, in 2021.

Catalina 10.15.x (2019-20)

This is the first version of macOS to use the new boot volume group, but is a half-way house to the full signed and sealed System volume (SSV) to come in Big Sur. It’s also the first fully 64-bit macOS, but remains Intel-only. Together these give it some of the advantages of later versions, but most of the disadvantages too. Another disadvantage for many users are the new media apps, such as Books, Music, Podcasts and TV, which replace iTunes. In Catalina, those are underpowered and unpopular as a result.

Apple currently provides security updates, including offline Installer packages, but those don’t fix all known vulnerabilities, and in any case are expected to cease this summer, before the release of macOS 13. From then on, Catalina will be left unsupported. If you’re currently running Catalina, now is the time to plan your next move.


Big Sur 11.x (2020-21)

The major structural change brought by Big Sur is the signed and sealed System volume (SSV). This takes the System volume from a Boot Volume Group (introduced in Catalina), seals it using a hierarchy of cryptographic hashes, makes a snapshot of it, then boots the Mac from that read-only snapshot. This enhances system security, at the cost of making updates less flexible. This is also the first Universal version of macOS, with full support for early M1 Mac models, making it the oldest version which can be run in a Virtual Machine on Apple Silicon.

Most users were less impressed by its redesigned interface, with rounded rectangles everywhere, and narrow iPad-style alerts. Bundled apps such as Music are improved, but still not comparable with iTunes.

Apple is expected to continue providing security updates to Big Sur for the next year, until the summer of 2023, but normally doesn’t fix any bugs which don’t affect its security. In contrast to previous versions of macOS, its security updates are numbered as patch updates to macOS 11.6, not as Security Updates. They also aren’t as complete as updates to 12.x, with some fixes appearing significantly later. Because they use the new macOS update installation mechanism, updates are only available through Software Update, and they can’t be downloaded for offline installation.


Monterey 12.x (2021-22)

This makes only minor structural changes in addition to those in Big Sur, of which the most significant is the introduction of paired Recovery volumes on boot disks for M1 series Macs. The emphasis has been on fixing bugs and consolidation, although the last significant bug affecting most users, a memory leak when using the Find feature in the Finder, is expected to be fixed in the 12.5 update. Many new features have been added, such as Universal Control, Live Text and Visual Look Up, and Shortcuts has been migrated from iOS/iPadOS to revitalise automation.

It looks increasingly likely that macOS 12.5 will be the last significant update to Monterey, following which Apple will release 12.6 in the early autumn/fall as its first security update. It’s expected to be supported by further security updates until the summer of 2024, when it will become unsupported.


  • El Capitan, macOS Sierra – last before APFS, vintage hardware only
  • High Sierra – limited and buggy APFS
  • Mojave – last macOS with 32-bit support, ideal in a VM
  • Catalina – 64-bit, boot volume group, half-way house, security updates ending soon
  • Big Sur – SSV, M1 support, new interface and media apps, support to 2023
  • Monterey – consolidation, last general update soon, then support to 2024.
  • Ventura – to be confirmed.