Hello,
It's 2.0b, I use the HDMI cable I received with the screen, on a PC for games and work. It all depends on how you use it (console or PC).
Yes, an HDMI 2.1 cable is compatible on the connector. You won't have the resolution and refresh rate of 2.1 but you'll be at the maximum of 2.0b.
HDMI 2.0b vs HDMI 2.1
https://www.coolblue.be/fr...HDMI 2.1 or HDMI 2.0
https://www.benq.eu/fr-fr...I use it on a PC with a 4080 Super and I'm very happy with it.
I hope I've answered your question.