A possible upgrade for the T-34-85 - anti-shaped-charge screens.
Those were fitted on many tanks in 1945, often improvised by the crews from what was at hand (though factory-made kits were easily available as well). Supposedly those would cause a Panzerfaust (or similar) projectile to detonate prematurely, severely reducing its armor-piercing power and saving the tank.
Panzerfaust attacks became a very common problem once the fight went into German cities. Often the attacks were from the sides, behind or even above (from windows), so those directions got the additional protection.
The screens did not improve the protection against any other kind of weapons than HEAT. A very similar system is still used today to protect vehicles from RPG fire.