Back in 2016 I wrote a Checkmk notification script that sends messages via a Telegram Bot. Only a few years later I got around and turned it into a real Checkmk package.
After switching to Checkmk 1.6 some months ago, all I had for notifications was email. During my christmas vacation I got notifications via Telegram set up again. As part of the setup I also brought the old code into shape and finally packaged it as a real Checkmk package to make installation easier.