Here is some explanation:
Your notification is delivered to your phone with FCM(Firebase Cloud Messaging), by the Telegram server sending notification with API Key coresponded to the App.
We third-party App developers are using the App configuration page on my.telegram.org to configure the API Key for our client.
However, the old FCM API was deprecated
last year and will be removed soon, and Telegram still hasn't updated its configuration page(which received no update for 10 years) to reflect the API changes.
