It has been asked many times before, but the topics have always been left unfinished, and it has been said to use FCM. Using Firebase used to be very easy. Since security measures are constantly changing, I could not send a message with PHP. I can send a test message from the Firebase site, but despite receiving support from artificial intelligence, I could not send a message with PHP. That's why I turned to systems like OneSignal. How can I receive notifications with Onesignal even if the application is closed? In previous topics, it has been said that Rest API is sufficient. Can OkHttputils read incoming messages in B4A when the application is closed? Can friends who use this service share an example?
