It's free of charge to get the installation package of KD Go!, also, you can have a look at users' reviews on Droid Informer. The app works fine on Android 4.0 and above. This download is completely safe. Koleje Dolnośląskie S.A. is the developer of this application that can be found in the Maps & Navigation category.
The tool was downloaded and set up by over 10K users and the most recent stable release was on May 28, 2018. On Google Play, KD Go! is rated 2.6 by its users.