went through tier 7 and tier 6, they got some nice buffs and a global hp buff of about 50~ HP for most tanks which is nice.
M6 also got speed, DPM, accuracy and gold ammo pen nerf so you won't see seal clubbers club as hard in it anymore. (see pic related)
BUGI and AMX M4 45 got their P2W damage increase prem ammo removed.

mid-tier tech trees buffs that caught my eye are AMX AC 46, O-Ni and P.44 Panthera.