He closed his laptop. Then he opened a text file and typed:

Catalina 10.15.7 is the last version to support the 2012 Unibody MacBook Pro and the 2012 Mac mini .

This is the "Hub" method for technicians. A USB allows you to install Catalina on multiple machines or perform a clean erase.

To install Catalina on multiple Macs or perform a clean install, use a USB drive (minimum 16 GB):

Just remember: if you are going back to Catalina, ensure you have a backup, stay off unsecured networks, and enjoy the era of the Intel Mac one last time.