Am I able to update iMac ( 21.5 late 2013) to the new iOS?
Am I able to update iMac ( 21.5 late 2013) to the new iOS?
iMac 21.5″, macOS 10.13
iOS is the operating system for iPhones, macOS is for Macs.
A2013 iMac can be upgraded to Catalina 10.15.7 but no later. See: How to download macOS - Apple Support
Note that if you upgrade to Catalina you will also need to update any non-Apple 32-bit apps you have. To identify those apps, see https://www.stclairsoft.com/Go64/