The really significant Changes are to the front and some to the side armor.For the back and turret I can not find any reliably significant changes. Though the suspension and transverse rear transmission are still no damage hit boxes ( the blue parts of the armor profile pics). Tier X left and Tier IX right. At all times great pains were taken to get alignment and impact points the same for both the live client and 9.22 test client. Screen shots taken with Tank Inspector.
As you will see there is very little room for error when shooting the rear sprocket and trying to get a penning shot, also the hull bottom is quite high up.