We have just published new free apps for learning Polish language for Russian and Ukrainian speakers.
You can download them from Google Play for free:
Polish for Ukrainian speakers
Польська мова безкоштовно
https://play.google.com/store/apps/details?id=pl.tweeba.mobile.learning.uapl
Polish for Russian speakers
Польский язык бесплатно
https://play.google.com/store/apps/details?id=pl.tweeba.mobile.learning.rupl