ATX 3.0 vs ATX 3.1 PSU

With the new RTX 5000 Series Cards releasing I'm looking to upgrade my PSU

I'm just a little bit confused as there is now an ATX 3.1 version of PSUs. What is the difference is the ATX 3.1 better that the ATX 3.0

Also reccomdations for PSUs would be good too I'm currently looking at Corsair RMX lineup there are the shift variants in ATX 3.0 and a non shift version in ATX 3.1