First of all thank you for maintaining this container, it's working very nicely.
Are there any news about a possibility to get some notifications from the container?
Personally I would prefer email since I'm not using telegram.
The lucky backup container (https://hub.docker.com/r/ich777/luckybackup) has email notifications using a simple perl script which gets the required configuration parameters over the command line. It's called sendemail. You can find it here
https://github.com/mogaal/sendemail
http://caspian.dotconf.net/menu/Software/SendEmail/
When the required perl modules are installed it even has TLS support. If you could incorprate this into the image, it would be easy to configure email notifications using the Pre-Backup und Post-Backup Shell Commands.
I tried to copy the script and the perl binaries into the image myself, but i failed since sh claimed that it could not find the files although the permissions seemed to be correct.
Or should I use the sendmail executable which can be found in the image? I had no luck using it either.