The T-55 was a completely modern tank in the late 1950s and early 1970s. In the 1980s, many tank upgrades were carried out (T-55M, T-55MV, T-55AD and others) in order to increase the firepower and protection of an outdated tank by that time. In the 1990s, some Eastern European countries (Romania, Slovenia and others) also carried out modernization.

Anti-tank guided missiles Bastion pierced 550 mm of armor, which clearly does not correspond to modern indicators (the booking of modern modifications of the M1 Abrams is at least 700-mm against cumulative ammunition and at least 450-mm against subcaliber plus the angle of inclination of armor plates, British Challenger 2, FrenchLeclerchave even more powerful booking). Also, the upgraded versions of the tank (T-55M, T-55MV) have extremely weak armor. The T-55MV can withstand cumulative ammunition in the frontal projection with armor penetration less than 250 mm along the normal (at an angle of 90 degrees to the armor). The armor penetration of the RPG-7 reaches 600 mm behind ERA. Even the 1970-80s guided anti-tank missiles have 400-800 mm armor penetration. The T-55M has additional armor plates (armor is equivalent to 300-400 mm), which, however, is not enough, but the mass is much greater than that of other T-55s (40 tons versus 36-37 for other modifications). Over the years of the war in Syria, government forces lost more than 800 tanks, most of which are T-54/55 and T-72M. For 2017, tanks were removed from service in Russia (remain in storage), India, Poland, Germany (moved from the GDR) and other countries. However, in African and some Asian countries, upgraded versions of the tank will be in demand for more than a decade.