TAZ 5 firmware 1.x 2.x differences

There are several locations to receive firmware from. When in Cura I can install the latest firmware to On the Lulzbot download page there is linked: http://download.lulzbot.com/Software/Marlin/

I can see also there is a 2.x firmware available: http://download.lulzbot.com/Software/Marlin/

What is this firmware for? Is it ok to test this with a TAZ 5?