A revision is an indicator of a change to the original motherboard.
One can not upgrade your motherboard from one revision to another.
Most of the time, it is for minor improvements.
But sometimes it is to enable support of newer cpu's, or a newer ram tech.
Your motherboard IS COMPATIBLE with your CPU. Here is the compatibility list for your motherboard (all revisions) https://www.asus.com/Motherboards/P8H61M_LX/HelpDesk_CPU/