Macbook IOS High Sierra 10.13.6 update

You can help from their contact support

I also have a 2011 MacBook Pro. I had Mojave on it for a while via a "patcher" utility, but at this point, Adobe requires Big Sur or later for their current apps. I recommend for almost everyone that they stay with supported OS versions.

FWIW, I was at Best Buy (Metro Detroit area) this week and they had two open box M1 Mac mini computers for $493 each. If I was on a tight budget, I'd pick up one of those, get a used display, keyboard, and mouse from a thrift store, and I'd have a nice little setup for just over $500 that was current and supported and would run Adobe apps well.

I'm afraid High Sierra is the last version supported on old iMacs. However, you can still use 2019 versions (from ProDesignTools website). It will validate just fine with your new license.

For iMac 2010/2011 users running High Sierra

This worked for me for multiple Adobe software that I needed (and licensed for):

1. Uninstall Creative Cloud App if it is newer than 2020. You might need to uninstall all existing Adobe software to do this.
2. Download 2019 versions of the software from ProDesignTools (If you managed to get any 2020 versions from chat agent, old iMac or other means, you can use them as well)
3. Important: Disconnect from the internet!
4. Install your software, work your way up by year, beginning with 2019, then 2020.
5. Connect to the internet and allow Creative Cloud App to update and retrieve your licensing info.
6. Done