It just worked for me. But I don’t have any gear older than 2015. Here are the device requirements: https://support.apple.com/en-us/HT212757

Looks like you need a Mac from 2015 or newer and an iPad from the same year. Depends on the model though. Similar to Sidecar, I think it depends on video encoding/decoding features introduced in Skylake chipsets, along with some newer version of Bluetooth.

There might be some hacky stuff you can do to get it to run, but I wouldn’t expect good performance or reliability.

You could always run the iPad with calendar/reminders in split screen with no Universal Control - if you have a gorilla arm.