As you may know Polish tanks are making their way into the game, WG has shared the first official screenshots and info about it, its a tier IV Medium tank which is most likely to be a Premium.
The development of this medium tank took place in Poland, January 1937 with “Czołg średni w/g proj. B.B.T.Br.Panc.” as project name.
In October. 1937 a variant was proposed by the Technical Research Armored Arms Bureau (BBT Br. Panc.) by Major R. Gundlach.
The project was suspended and only mock ups were created.
Highest quality screenshots, sent by WG itself: