It took quite some time until I realized that I don't get notifications anymore on any of my Arch-based installations, but when aarchup didn't chime up even after days, I've finally noticed that there must be something wrong.

The culprit is the new autostart file coming with xfce4-notifyd 0.6.2:

[Desktop Entry]
Type=Application
OnlyShowIn=XFCE;
cp /etc/xdg/autostart/xfce4-notifyd.desktop /home/cobra/.config/autostart/
G dd ZZ