Software update required to connect to iPhone XR?

Hello sje45,

We understand that you need to update your computer in order to connect with your iPhone. The late 2012 iMac can update to macOS Catalina, per: macOS Catalina is compatible with these computers - Apple Support

Here's how you can update to it: How to get old versions of macOS - Apple Support

Thanks for using Apple Support Communities!

You do not need to update the Mac OS. Take a look at this.

If you see "Software update is required to connect to your iOS device" on your iPhone, iPad, or iPod touch - Apple Support

Understood, sje45,

Your Mac is compatible with syncing to the iPhone XR. It will use Finder, and those steps are located here: Use the Finder to sync your iPhone, iPad, or iPod with your computer - Apple Support

If you have any questions on the process, let us know.

Cheers!