New update crashes in multiplayer

I just updated and I crash every time I try to open a chest in my son's server, he also crashes when opening a chest in my server. I am playing on an iPad first generation with version 5.1.1, and he is on an iPad 2 with version 6.0.1. We also tested it with my other son's ipad 2 with version 4.3.5. Please fix. I love the game however this issue makes it impossible to play multiplayer.