Rated 5 out of 5 stars

It still works, but needed "Disable Add-on Compatibility Checks" extension to bypass version compatibility.
Could you please update your "DSN settings" addon to make it officially compatible with Thunderbird 45, thanks!

Rated 4 out of 5 stars

I installed the latest version yesterday, sadly do not receive any delivery notifications.

This add-on only adds UI settings for sending DSN.
If you do not receive any notifications, it's probably because your SMTP server does not support DSN.
In order to check that, create a telnet connection to port 25 of your SMTP server and type "ehlo test". The server should answer "250 DSN" if it provides DSN.