A hybrid app developer and Hybrid App Development Company used to have faced this situation: The database on the remote server is not updated with the InApp Purchase from apple and the app user who already has subscription has to go for yet another subscription with the counter version in Play store. Now this scenario is no more a trouble for a hybrid app developer and hybrid app development companies. Apple is not allowing server notification.
If your app offers auto-renewable subscriptions, you can receive server notifications from the App Store about key events by setting up an optional URL that links to your server.
Before sending a notification to your server, the App Store will try to establish a secure network connection with your server by using App Transport Security (ATS) protocols. If a secure connection cannot be established, notifications will not be sent to your server. See Requirements for Connecting Using ATS to learn more about security requirements.
After a secure HTTPS connection has been established, the App Store will deliver JSON objects through an HTTP post to your server for key subscription events. See the In-App Purchase Programming Guide to learn more about the contents of this HTTP post.
Use server notifications together with Receipt Validation to validate a customer's current subscription status and provide them access to content or services from within your app.Required role: Admin, App Manager, Marketer, or Technical. See Role permissions. From the homepage, click My Apps, then select the app. 1. The App Store page opens with App Information selected. 2. Scroll down to General Information, and then go to Subscription Status URL. 3. Enter the URL, then in the upper-right corner, click Save.
Source of Information: https://help.apple.com/itunes-connect/developer/#/dev0067a330b