On the 10th of February, Telegram sent the following message to
those with an application registered on https://my.telegram.org.

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Telegram API Update. Hello [REDACTED]. Thank you for contributing to the
open Telegram ecosystem by developing your app, [REDACTED].

Please note that due to recent updates to Telegram's handling of SMS and
the integration of new SMS providers like Firebase, we are changing the
way login codes are handled in third-party apps based on the Telegram API.

Starting on 18.02.2023, users logging into third-party apps will only be
able to receive login codes via Telegram. It will no longer be possible
to request an SMS to log into your app - just like when logging into
Telegram's own desktop and web clients.

Exactly like with the Telegram Desktop and Web apps, if a user doesn't
have a Telegram account yet, they will need to create one first using
an official mobile Telegram app.

We kindly ask you to update your app's login and signup interfaces to
reflect these changes before they go live on 18.02.2023 at 13:00 UTC.

This change will not significantly affect users since, according to our
research, the vast majority of third-party app users also use official
Telegram apps. In the coming months, we expect to offer new tools for
third-party developers that will help streamline the login process.