With the appearance of the Soviet T-34 and KV-1 tanks, the Panzer IV Ausf. F2 was made as a stopgap solution with a new and more powerful KwK 40 L/43 gun. After three months into production, the Panzer IV was upgraded again to the Panzer IV Ausf. G. The Ausf. G featured a stronger 80 mm thick front glacis armour with 30 mm side armour. Some weight-saving techniques were put into play, but the tank still weighed about 23.6 tons and put strain onto the driving system. Some simplification went into the tank such as the removal of the vision ports on the sides of the turret. The Panzer IV Ausf. G was well-liked by the armoured crews due to increased armour and lethality against the progressively stronger Allied armour such as the T-34s and the M4 Shermans. While the 50 mm armour before was deemed very vulnerable to the Allied guns, the 80 mm caused some headaches among Allied tankers, though could still come on-par in performances. At this point, the newer Panther tanks in production should have replaced the venerable Panzer IV by now, but production problems and low quantity meant the Panzer IV was staying at the main tank for the German Army for a while. The Panzer IV Ausf. G was then upgraded again to the Panzer IV Ausf. H, which would become the most numerous variant of all the Panzer IVs.