Is it too late to update from OS Sierra to OS High Sierra

Unless you have a compelling reason to remain with a pre-Catalina 10.15 OS, you can give your Mac the longest productive service life possible by upgrading to the latest OS the computer can run; macOS 12 Monterey.

➡️ macOS 12 Monterey is compatible with the Macs listed here

About a year ago I did that very thing but within a Parallels VM - I went to the App Store (which you can't now do in Sierra) and searched for High Sierra. The option I got was not ‘Get' but ‘Install’ which means I must have previously downloaded High Sierra and the App Store detected it, and I went ahead and installed. However, whether you can now get the High Sierra installer is another matter, though worth tryinng - High Sierra compared to Sierra is a bit like 10.6 compared to 10.5, i.e. not much difference in appearance, but a lot of changes ‘under the hood’.

Catalina, Big Sur, and Monterey break 32-bit applications. None is among "the recent three" which vendors like Adobe and Microsoft support.

However, all are good enough to run current versions of

• The Firefox web browser
• The LibreOffice office suite
• The GNU Image Manipulation Program (GIMP)
• The commercial Affinity V2 applications (Photo, Designer, Publisher)

Big Sur and Monterey are good enough to run current versions of several other browsers, like Brave and Opera. Thus, if you upgraded to Monterey, there are some applications you might be able to use to extend that Mac's useful life.

SimplyLola wrote:

Thank you for this information. It is very helpful for deciding what I should do. I looked it up and now understand that some applications may no longer work if I go beyond High Sierra due to 64 vs 32 bit. I don't use Microsoft of Adobe applications. I would be happy if I could continue using Firefox.

It sounds like you are running Firefox now. The version that runs on Sierra, Firefox 115 ESR, stopped getting new features a long time ago. Mozilla has been providing it with "critical security updates" – but they may stop doing that in August 2025.

After you upgrade to Monterey, you can download and run the current version. I'd expect Monterey to be enough to keep up with Firefox updates for at least a couple of years. After that, Mozilla might release an ESR version for Monterey – one more recent than the ESR version for Sierra – which you could use a few years longer.

Chances are that you'd want to replace the 2017 MacBook Air long before you ran out of options to run Firefox on Monterey.

You have another choice with High Sierra : Firefox Dynasty, which is based on the latest version of Firefox. You can get it from this page - look for Releases down on the right hand side, which if you click it will get you the latest version of Dynasty. It behaves exactly as Firefox but will last much much longer than FF 115 ESR

https://github.com/i3roly/firefox-dynasty

Back up your data, check the application compatibility table, click here, and then on the download link for it.

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1. Installing High Sierra requires 14.3GB of free space.

2. The installer is designed to be self-explanatory and doesn't list complex choices.

3. Yes; an issue any occur at any time, but is more likely while upgrading.

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