For starters, great game, an awesome trip down memory lane and seems to have endless possibilities

I’m experiencing a crash every time I try to upgrade (I assume the green arrow pointing upwards is upgrade) bus depot. This is on iPad Pro 11” (iOS 12.1) and game version 1.7.15.
I don’t know if this is the case for other buildings as I’ve only been playing for an very short time.
Best regards!