I've had apps stop working after upgrades on every device I have ever used.
It's important that the developer keep up with an evolving API and if they plan to use experimental features that aren't locked in yet, they should make note and be prepared for if/when it's taken out or changed.
Unfortunately, no matter what device you use, there will be developers who fail to maintain their apps.
Which is swell if you're an application developer. But for the end users it means that apps may suddenly stop working if they upgrade the OS.