Telegram sent a notification to third-party app developers today.
Starting from February 18, when you first log into any desktop and web Telegram client (doesn't matter 3rd-party or official), there will be only one way to receive a confirmation code - get it in the Telegram mobile client on your mobile device. No SMS anymore.
Thus, if you want to add a Telegram account to Miranda, you will need to have a telegram client on your phone.