It is difficult to know when the Slavs separated from the Balts. The Kiev culture is the only one that can be definitively attributed to the Proto-Slavs. Regarding earlier cultures, there is no certainty. There are many contradictory and contested hypotheses. There is no consensus concerning their relationship with the Proto-Slavs. The cultures most frequently discussed are the Milograd culture, the Dnieper-Dvina culture, the Zarubintsy culture, and the Chernoles culture.  In my opinion, the Kiev culture derives mostly from Dnieper-Dvina (Днепро-Двинская культура).

The only new map is the sandbox map of the Germans. But I don't know whether sandbox maps were shown by that filter in the past.

In the past I remember a map filter for "new maps", but I cannot see it in 0.28-rc1. Are there no new maps in this release or the filter is just missing?

UPDATE: Version 0.11.1 Balance Increased income from retail trade (multiplier = 3.25) Increased income from deposits from 1 to 1.5% The amount of resources on the map has been increased by 4 times. Bot The resource gathering speed for the player and the bot is the same and does not depend on the selected game difficulty level.  Added a garrison function for training units (infantry and cavalry). After recruitment, idle units will enter the building to gain experience and increase their rank. The maximum number of support units is set at 1/3 of the unit limit.  

Thank you for taking care of it.