We recently upgaded the boards on these with some new features.  Hence the increase in model number from 3.1 to 3.1.1.  To see the difference or to do the upgrade you can see  here that explains this upgrade in more detail.

If you currently own a 3.1 unit all you will need is the LCD Control Panel. You will not need a new PCB Board (Power Board)

BrewZilla Generation 3.1.1 - LCD Control Panel