This discussion immediately brings to mind all of the iOS apps that become completely unusable the day a major iOS update is released, and then take a week to fix.

I get that not everyone has spare time and energy, but it doesn't take that long to grab a beta, put it on a device (or load up the simulator) and find out. Leaving it until the last minute just forces you into a panic, and seems irresponsible when you had months to just test your product.