The current stable version of Dunst is 1.6.1 released on Feb 21 2021.
The most important update from the previous version is the addition of the dunstctl command and dunstify utility, a drop-in notify-send replacement (which existed for a while, but wasn’t installed by default). The internal keyboard shortcut support in dunst is now considered deprecated and should be replaced by dunstctl calls. You can use the configuration of your WM or DE to bind these to shortcuts of your choice.
Additionally, another long requested feature implemented is RGBA/transparency support. Given an active compositor you can now add an optional transparency component to all colors in #RRGGBBAA format.
As mentioned above, two new binaries are now installed by default, dunstctl and dunstify. libnotify has been added as a dependency as it’s used internally by dunstify.