Parse is shutting down, and if you want your app to keep working, you’ll need to move to something else. I’d recommend doing it sooner than later. Thankfully our app isn’t out for another few weeks, and since the only thing we were using Parse for was push notifications, it wasn’t more than a couple hours of work to switch over to something new. The thing we found to handle our push notifications was One Signal.
Aside from Parse I’ve also used Urban Airship, Push IO, and a custom push server. Custom was definitely the worst. If I were writing the backend myself, custom might not have been so bad, but since I was always working with other developers, it was always a pain because it required involving someone else to test the thing and there was always something wrong with the certificate setup on the server. Out of all of those OneSignal has been the easiest, followed by Parse. I like OneSignal better than Parse though because it’s just push instead of one part of a larger thing that sort of expects me to be using their whole platform.