IMPORTANT: This is not our insider so I cannot vouch for the information listed below.
Rykoszet’s insider tells that the Studzianki map is now being made in HD quality, and it is likely to be introduced along with a Polish tech tree. The date of release for the Polish tanks is not specific – but the insider assumes that at this moment the most likely date (which could be changed at any time) is the second half of 2018. If developers encounter difficulties, though, there is still the possibility of it being postponed again.