Update 4.91

Update 4.91
* New game type - Custom Game
* New combat effects on London map

* Found and fixed a bug with the inability to connect players to each other
* Fixed crashes from the game on some mobile devices on certain maps
* Fixed a bug with the end of the battle when the game is accidentally minimized
* Fixed a bug with clan research
* Fixed critical zones of Nightmare tanks, fixed sights of some tanks
* Other technical fixes