So you know how as a player levels up, they are restricted from entering lower level matches, even if they have low level equipment? What are the cut-offs exactly? First its 10, now I am at 20. I would like to battle at lower levels for a while, but I would hate to make a level 20 build just as the lower limit rises to 30.

It's just levels 10 and 20.

Or maybe it's been changed from 10 to 20...
Either way, you're find to play at lvl 20 whatever your experience level.