So later version of this shaped charge has possibility to be effective against such armour? And can you share what is known belly armour for T-series tanks? Thanks.
Well, AFAIK for "T" tanks there were also upgrades for belly armor. I don't know how it looks in Russia or Ukraine, but for example in Poland, our T-55 modernization, the T-55AM "Merida" had improved protection of the hull belly, I heard that this improvement was also slightly problematic due to shape of additional belly plate, which could cause some downgrade of vehicle mobility in difficult terrain.
The T-55AM "Merida" is very similiar to other upgrades of the T-55 tanks, like T-55AM2B and T-55M so it is very possible that all of them had the same belly protection, just as they share BDD addon armor for turret and hull.
Also T-72M1 upgrade, the PT-91 "Twardy" have improved belly protection.
If I am correct, BM "Oplot" also have improved belly protection, Andrei can say more probably.
However standard belly protection, is as I said, approx 20-40mm thick RHA plate.