Board Thread:General Discussion/@comment-24.79.24.47-20141222121516/@comment-5022157-20150101064920

7 stars should only be for the OLDEST units. And UBB level up doesn't work that way you have to fill a bar that counts your BC in order to unlock the UBB bar for a single unit which in turn you need to fill up and to use it again you have to repeat the entire process