Can I upgrade my iMac 27" from macOS X Yosemite to Sierra?

Next stop from OS X 10.10 Yosemite is OS X 10.11 El Capitan, then macOS 10.12 Sierra, and anything that can run macOS Sierra can also run macOS 10.13 High Sierra, or potentially later.

Available macOS upgrades: How to download and install macOS - Apple Support

An iMac from 2009 and later can run macOS 10.13 High Sierra:

macOS High Sierra - Technical Specifications

An iMac 27” from 2013 can also run macOS 10.15 Catalina.

Have a complete and current backup created before the upgrade, as there is no downgrade available if a problem or incompatible app should arises.

The Go64 tool will find apps that won’t run on macOS 10.15 and will need an update, upgrade, replacement, or retirement.

MCink wrote:

Thanks. I NEED to get to OS X 11 (It is a requirement of COMCAST)

Did they say OS X 10.11 (El Capitan) or macOS 11 (Big Sur)? One is very old, while the other just recently fell off the list of the "most recent three" that some vendors go by when deciding what OSes to support.

Do you think I can do that? I will read what you sent me. But thought if you knew off the top of

your head... Thanks. the info was helpful MC

What does it say about your Mac in the About This Mac dialog in the Apple () menu?

• Macs with hardware model dates of 2013 (plus or minus) can run OS X 10.11 (El Capitan).
• iMacs with hardware model dates prior to 2014 cannot run macOS 11 (Big Sur).

You’ll want to upgrade to macOS 10.15. Your Mac cannot run macOS 11. It’s too old. But you can get to macOS 10.14 and macOS 10.15 with Safari, which seemingly is supported.

Comcast is confused about the naming.

They presumably meant “macOS 11”, not “OS X 11”, or you can use macOS 10.14.4 or later with Safari.

A mistake which doesn’t help with support issues.

Here’s the image again, without the sensitive data:

MCink wrote:

So it looks like the answer is NO? Any tricks? Suggestions?

It looks to me, as it does to MrHoffman, that Comcast made a mistake in writing down the name of El Capitan. If "OS X 11 or later" meant Big Sur, then the requirements in parentheses ("OS X 10.14.4 if using Safari") would not make any sense, since if you had Big Sur, you would by definition have something later than Mojave.

Another indication that "OS X 11" is likely a mistake is that Comcast called Mojave "OS X" rather than "macOS." The 10.14.4 is unmistakably Mojave.

Then there's the "download Safari" link. That probably points to an outdated version of Safari that is older than the versions that come with Mojave and Catalina. Apple originally released Safari by itself (and even released a version for Windows), but after a while, they started bundling Safari updates with macOS ones.

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Depending on the applications you rely on now, I would suggest upgrading your Mac to Mojave or to Catalina.

How to download and install macOS - Apple Support

If you go with Mojave,

• 32 bit applications will continue to work.
• You will be able to upgrade to Firefox 115 ESR . Mozilla says that they will provide "critical security updates" for it until September 2024.

If you go with Catalina,

• 32-bit applications will stop working.
• iTunes will go away, replaced by separate applications: What happened to iTunes? - Apple Support
• You will be able to upgrade to the current version of Firefox.
• You will be able to run the current version of LibreOffice.
• Your OS will still be old enough that you may not be able to run current applications from the likes of Adobe and Microsoft.

MCink wrote:

Thanks. I NEED to get to OS X 11 (It is a requirement of COMCAST)

Do you think I can do that? I will read what you sent me. But thought if you knew off the top of

your head... Thanks. the info was helpful MC

Check the details of the Comcast requirement again.

I doubt Comcast specifically requires OS X 10.11. That's very old. There'd be complaints about that. Lots of complaints.

I expect Comcast requires OS X 10.11, or later.

It is also possible that some Comcast app or service uses macOS 11 as a lower bound, too; macOS 11 or later.

PS: Some care around the Apple macOS version numbers is warranted too, as macOS 11 is the next release after macOS 10.15, and OS X 10.11 is rather older than macOS 11. In a manner of consideration, Apple chose to use macOS 11, rather than what would otherwise have probably been known as macOS 10.16.

When Apple changed over from the classic Mac OS to the Unix-based Mac OS X, they kept the leading "10.0" for sixteen major versions. So you have Mac OS X 10.0 ("Cheetah") through macOS 10.15 ("Catalina").

Then they went back to changing the leading number, so you have macOS 11 ("Big Sur") through 14 ("Sonoma").

"OS X" was never a prefix for Big Sur, and "11" (without a leading "10.") was never a designation for El Capitan … hence the ambiguity in a requirement for "OS X 11".

Other funny naming schemes:

• Intel named the successor to the 486 the Pentium. (A pentagon has five sides.). Then they called its successors the Pentium 2, Pentium 3, and Pentium 4 ("five two", "five three", and "five four"). Later, Intel gave the Pentiums names like Pentium Silver J5005 (I kid you not!).
• Microsoft jumped straight from Windows 8 to Windows 10 without ever releasing a Windows 9.
• Some high-rise buildings don't have a 13th floor. The numbering skips straight from 12 to 14, or the 13th floor is labelled "12A", "Mezzanine", etc., presumably because of the superstition about the number 13 being unlucky.