Apple’s New Year is coming: macOS 15, 14, 13 and 12

In just over ten days time, Apple starts its New Year with the opening of WWDC on 10 June. With that come the first beta-releases of macOS, iOS and all its other OSes, major product announcements, and bad news for those whose older Macs and devices are no longer supported.

This cycle, Apple seems to have got ahead of itself, in releasing macOS 14.5 in May rather than July, a full two months earlier than usual. This may be because it intends to release macOS 15 early in September to coincide with new Macs, or it might mean that 14.6 is due in July.

After a late start, Big Sur reached 11.5 in July, and 11.6 in September 2021. Monterey followed similar dates in 2022, as did Ventura last year. Each of those also had one or two unscheduled security patches released between their .5 and .6 minor versions, during high summer.

Although Apple’s support has never been cast into writing, for many years now it has worked thus:

The current version of macOS (n), at present Sonoma but handing over to macOS 15 around September, receives full support, addressing both security and general bugs, and receiving new and enhanced features.
The previous version of macOS (n–1), at present Ventura but handing over to Sonoma around September, receives only security fixes, normally not as complete as those fixed in the current macOS.
The version before that (n–2), at present Monterey but handing over to Ventura around September, receives only security fixes, normally even less complete than the newer version.
All versions before those, including Monterey from around September, are unsupported, and only very rarely receive any bug fixes at all.

Monterey

The final security update to macOS Monterey is due in September, and likely to be 12.7.6 or later, depending on whether there are more vulnerabilities to be fixed. If your Mac is currently running Monterey and is supported by Ventura or later, now is the time to plan its upgrade before Monterey is abandoned for good.

Ventura

This reaches the end of its first year of security-only updates in September, when it should be updated to 13.7 ready for its final year of support until that completes in September 2025. If you intend upgrading to Sonoma, now is the time to plan that.

Sonoma

So far, Apple hasn’t released any betas of 14.6, suggesting that’s likely to be the first of its versions to include only security fixes. It should then receive further security-only updates until September 2026, when support is expected to be withdrawn. If you intend upgrading to macOS 15, you’ll need to monitor progress with its beta-releases to help you decide when’s best to do that.

Public beta-releases of macOS 15

The first beta-release is normally made to developers only on the opening day of WWDC, following which it may receive one or two updates. Release to public beta-testers then follows about a month later, in July. As with last year, once you have registered your Apple ID for beta-releases, you can choose to receive them in Software Update settings by clicking on the ⓘ button on the Beta Updates row. This is considerably easier than previously, but can also result in your inadvertently installing a beta on a Mac not intended to be used for them. I will provide further advice nearer the time as to the precautions you should take when installing betas for a new version of macOS.

Which Macs will support macOS 15?

Until Apple announces this, no one outside Apple knows. What we do know is that the list of existing Macs supported won’t be any larger than those supported by Sonoma, that the decision is dominated not by engineering but marketing, and that all Apple silicon Macs will be supported.

That leaves one Intel iMac model without a T2 chip (iMac19,1) looking vulnerable, as it was supported by Sonoma largely because it had sold strongly into Enterprise and other volume users. Older T2 Macs, including the iMac Pro and early MacBook Pro models from 2018, must also be looking vulnerable this year.

SilentKnight and Skint

The new betas will bring new firmware versions, which presents a problem to SilentKnight, as it can only consider one version to be ‘correct’ for each model of Mac. This means that, if you continue to run a release version of macOS, SilentKnight’s checks will remain correct for that. If you install a beta of macOS 15, then SilentKnight won’t report it as being incorrect, but will note that it’s a higher release than that expected.

Skint should recognise that your Mac is running a pre-release version of macOS and report that.

I have already updated the databases used by SilentKnight and Skint ready for the first beta-release of macOS 15, although I can’t confirm those version numbers until I have a copy up and running here.

In the next few days, I will be releasing new versions of SilentKnight and Skint that should work fully with macOS 15, and will keep them up to date as the betas change. My aim is that both apps will be as useful to those in the beta-programmes as they will remain for those running release versions of macOS. Please bear with me if I might fall a little behind the betas.

Key points

Support for macOS 12 Monterey will cease by September. Now is the time to plan your escape.
macOS Sonoma will transfer to security-only support by September. During WWDC check whether your Macs are supported by macOS 15 and start planning their upgrades.
SilentKnight and Skint updates are coming shortly.