How can I upgrade this computer to OS X 10.12 ?
IMac
iMac 21.5″, OS X 10.10
Back up your data, check your applications for compatibility, click here, and then on the download link for a newer OS. A 21.5-inch iMac can be upgraded at least as far as High Sierra.
Catalina and higher won't run 32-bit software; download and use Go64 as well as using the first link above.
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