It’s strange to think that, as we’re wondering whether and when to upgrade to Sequoia, Apple’s engineering teams are already at work on macOS 16. While they’re thinking out what we’ll chew over next summer, you may well be asking if you should upgrade to 15.0 next week, wait for the AI features coming in 15.1 next month, or leave your decision until 2025?

For those with Macs and iPhones that can both be upgraded, iPhone Mirroring is probably the most obviously attractive new feature. It completes the integration of Continuity, and could transform your workflows. Fortunately for such a key feature, it should work with all supported Macs, not just Apple silicon models. There’s one small and temporary disappointment, though, as drag and drop between Mac and iPhone isn’t expected in 15.0, but in an update “later this year”.

The new Passwords app should spare you from wanting to pay for a third-party password manager. This is much more than just shelling out the existing Passwords feature from Safari and System Settings, and at last gives full control over passkeys and other shared secrets in your Keychain in iCloud.

Although some see Sequoia’s new dislike for apps that aren’t notarized (or from the App Store) as an unnecessary burden, for most of us this will raise the bar against running malware and increase our margin of safety. It has been some time since any malicious software has been successfully notarized, and most of the current epidemic of stealers aren’t even signed with a Developer certificate. Instead, they usually prompt the user to open them using the existing Finder bypass, something that no longer works in Sequoia without explicitly and individually giving permission to that app in Privacy & Security settings.

It will be interesting to see how malware developers respond to this challenge, as trying to give the user detailed instructions as to how they can be run without being blocked by Gatekeeper should now arouse the suspicion of even the most careless and inattentive.

While we’re on the subject of security, remember that Sequoia is now the only version of macOS that gets full security updates over the coming year. While Sonoma and Ventura will still get some, if you want the lot then you’ll need to upgrade. Monterey, of course, now gets none at all. This gets more brutal when considering other bugs that aren’t relevant to security: those will only be fixed in Sequoia, not even in Sonoma.

For those who virtualise macOS on Apple silicon, support for Apple ID gives VMs access to iCloud Drive at last, although it stops short of enabling the App Store or its apps, so isn’t as useful as it should have been. There are two important restrictions to this:

• Apple ID can only be used in a Sequoia guest running on a Sequoia host, and
• the Sequoia VM has to be built from a Sequoia IPSW file, and can’t be upgraded from a Sonoma or earlier VM.

As long as your Mac stays with Sonoma, you won’t be able to use Apple ID in any of its VMs, including Sequoia. This still leaves us with the paradox that Apple wants us to buy and run apps from its App Store, but VMs are the one place where you can’t use them.

Among the less prominent improvements that have caught my attention are a timed messaging feature of Send Later in Messages, and a batch of improvements in Freeform. If you’ve come to like that relatively new app, you should find Sequoia worth the effort. I’ve also been impressed to see one of the oldest bugs remaining in the Finder has finally been addressed in macOS 15. I’ll be putting the bunting out in celebration after I’ve upgraded on Monday.

As with Sonoma, some of the most important new features haven’t been documented even for developers. Among those are changes to XProtect in terms of its updating and management, and speculation as to how that might affect its function. As I have explained, XProtect’s detection rules have grown enormously over the last few months, and it’s likely that Apple intends improving how XProtect can apply its Yara rules, and making their updating more efficient.

Finally, Sequoia is almost certainly going to be delivered as if it were an update, and won’t download its installer app unless you’re upgrading from a significantly older version of macOS, just as has happened in all recent macOS upgrades. Remember that upgrading macOS these days comes with a one-way ticket: changing your mind afterwards will cost you a lot of time and messing about to step back to Sonoma. However, accidental upgrades shouldn’t be feared. For instance, if you inadvertently click the Install all updates button in SilentKnight and want to reverse that for a macOS update, let the download complete, shut down, start up in Safe mode, wait a minute, then restart in normal mode.

Whatever you choose tomorrow, I hope it works well for you. And in case you’re wondering, if you’ve got an Apple silicon Mac, you’re going to love 15.1.