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 Name=Xfce Notification Daemon Exec=/usr/lib/xfce4/notifyd/xfce4-notifyd Icon=org.xfce.notification OnlyShowIn=XFCE;
Only show in XFCE? As OpenBox user, I feel seriously excluded and discriminated. Well, actually, we can just delete this line in a user context and thus continue as before:
cp /etc/xdg/autostart/xfce4-notifyd.desktop /home/cobra/.config/autostart/ vim /home/cobra/.config/autostart/xfce4-notifyd.desktop G dd ZZ