Broadcast to Telegram is a very simple plugin that lets you automatically send post notification to your telegram channel via an admin BOT.
It allows you to enroll multiple Telegram channels and you can choose, when sending, which channels make the notification to. It also allows you to choose which type of document is to be used with.
It also gives the possibility, when a document is updated, to know which channels have already been sent a notification and edit directly the Telegram original message, marking it as updated by the (M) symbol.