Updating Mac OS
I have an older MAC which runs off of Sierra 10.12.6. Is there a way to download the newest OS?
iMac 21.5″, macOS 10.12
Back up your data, check the application compatibility table, click here, and then on the download link for a newer OS. Your computer can be upgraded at least as far as High Sierra; it's not possible to tell what its maximum one is from the posted information.
Catalina and above won't run 32-bit software and split the functions of iTunes up; if you choose one of them, use Go64 as well.
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