Lost MacOS support with version 27 on iMac 2020.

If Apple continues with their current policies, until 29 comes out.

(260703)

FWIW…

"During the Platforms State of the Union at WWDC, Apple just announced that macOS 26 Tahoe will be the last release of macOS that supports Intel. That means from next year, major new versions of Apple’s desktop operating system will only run on Apple Silicon Macs (that is, 2020 M1 models and newer)."

If you're careful about your browsing habits, you could continue using that iMac for years after it stops getting new macOS updates. Especially if you installed a browser like Firefox once Apple started requiring macOS 27 or later to run the latest and greatest version of Safari. (Mozilla is still providing "critical security updates" for Firefox 115 ESR on Sierra – and Sierra is eight major versions behind Sequoia.)

From the WWDC25 Platform State of the Union transcript…

"54:56 And so, macOS Tahoe will be the final release for Intel Macs."

FYI,

When Apple switched from PowerPC processors to Intel processors, there were two versions of Mac OS X that ran on both: 10.4 (Tiger) and 10.5 (Leopard). Then the PowerPC machines were cut off.

There are five versions of macOS that run on both Intel and Apple Silicon processors: Big Sur, Monterey, Ventura, Sonoma, and Sequoia. With Tahoe, that will make six. The iMac (Retina 5K, 27-inch, 2020) originally ran Catalina, so it will have received a total of seven major versions of macOS. If I remember correctly, very few Intel-based Macs are getting Tahoe: yours is one of a handful of "lucky, last and greatest of their kind" ones.

That's why it's never a good idea to pay much attention to rumors. I could see if I had a need to have multiple apps on the same screen at once a 32" display could come in handy. But since I don't, I had no problem going from 27" iMacs to the 24" iMac. Because it's slightly smaller, it actually looks slightly sharper.

PaulB190 wrote:

Ok. Side trip.

Now that I know it’s one OS update then two years and done on my 2020 iMac do I run it out till 2029 or pop next year for a Mac Mini and a 32 inch Dell flat screen U3225QE?

Dell – Dell UltraSharp 32 4K Thunderbolt Hub Monitor - U3225QE

iMac (Retina 5K, 27-inch, 2020) - Technical Specifications - Apple Support

That's a 31.5" UHD 4K monitor with DisplayPort v1.4, HDMI, and Thunderbolt 4 inputs. I believe that Thunderbolt 4 accessories are supposed to be backwards-compatible with Thunderbolt 3 host ports – so the 2020" 27" iMac sitting on your desk could drive one (or two!) of these now, if you had the budget, and the spare desk space, and wanted the monitor now.

Then you could transfer the monitor to your next Mac, when it was time.

FWIW, I would have as well if I had read your question correctly. 😎

PaulB190 wrote:

Niel, thank you for actually answering the specific question. It’s appreciated.

Niel's brevity and specificity are legendary!

You might want to see how Tahoe runs on your iMac before deciding.