Will Siri work with 3rd party apps after update from iOS 9 to 10?
SiriKit, or third-party integration with Siri, is available on any device compatible with iOS 10. According to Wikipedia: 


  Siri is compatible with third-party app-specific requests, such as starting workouts apps, sending IMs, requesting the Lyft or Uber apps or to use payment functions.


Note that not all apps utilise SiriKit, and only those that do will work with Siri.