iMac Late 2015 (21 inch, mk442) screen flickering/weird colors/glitches/lines

[@mohammedmoh8491]

Nice good luck 🍀👍

[@thetitanofficiel4634]

Thank you guy ♥️

[@chriscampbell7991]

Where can I find this older os?

[@Bohdan_HI-TECH]

High Sierra can be still downloaded from Mac App Store: apps.apple.com/us/app/macos-high-sierra/id1246284741?mt=12

[@MassimilianoGallieri]

I have the same problem, same imac. I'll downgrade and let you know