Thanks to MicMac 80 for the link!
According to Ukraine Today, the 6x6 is a mortar carrier and the 8x8 is the infantry fighting vehicle version. I find the Ukrainian approach to armored vehicles frustrating. They're pushing mostly MRAP type trucks as IFVs, modifying Russian designed vehicles to sell overseas and have an approach of throwing everything against the wall and seeing if it sticks. I don't see a strategy coming from the Ukrainian Defense Ministry regarding procurement. During a time of war that seems wrong headed at best and plain stupid at worst.