I need to side cart my new MacBook Pro (16-inch, 2021) to my iMac (21.5-inch, Late 2013) but being told both Apple products must be updated to macOS Monterey. Is this true? If so, how do I get my iMac updated to macOS Monterey?
Welcome to the Apple Support Communities.
You cannot upgrade your iMac (21.5-inch, Late 2013) to macOS Monterey. It cannot be upgraded past macOS Catalina 10.15.
Also, "Sidecar" is for iPads and Macs: Use an iPad as a second display for a Mac - Apple Support.
Did you really mean "AirPlay to Mac"?
Jack
iMac 2013 support macOS Monterey
