How can I delete all my unlocked Content on Android?
And when comes a New Update/Version/patch of the Game?
On android it's a bit more complicated...
So there's this folder: Android/data/com.AnduoGames.ThirdCrisis/files
Which contains the gallery.sav file, which stores your progression in the gallery. Getting to that folder however, is different for each brand of android phone. Some even lock your ability by default to get there. You'll have to find out how to get to it yourself. Once you're there, just delete the gallery.sav.
Alternatively, you can delete the app before installing the update, this will also delete your savefiles though.