Some specific reasons, I have to downgrade my devices macOS from Catalna to El Capitan.
I have 2 devices
1. Macbook Pro(Mid-2015)
2. Mac Mini(2018)
I made a bootable USB flash with Capitan inside and can downgrade the macOS to El Capitan for Macbook. But the same bootable flash and process, I got the error message when I do it for Mac Mini. The error message is " a software update is required to use this startup disk"
Any one have a clue? Thanks
I need to clarify a bit on my previous post. Apple only supports rolling back to the version your computer would have shipped with when that model was released. The system requirements listed in the linked article will show how old of hardware you'll be able to run certain versions of Mac operating systems on.