I have an app that uses [NSUserDefaults standardUserDefaults] to store session information. Generally, this information is checked on app launch, and updated on app exit. I
I found NSUserDefaults to behave nicely on iOS 8.4 when using a suite name to create an instance instead of relying on standardUserDefaults.
standardUserDefaults
NSUserDefaults *userDefaults = [[NSUserDefaults alloc] initWithSuiteName:@"MySuiteName"];