GadgetBridge Notification Not Working

Hmm - that's odd - the F-Droid app doesn't seem to have been updating the apps for me.

I just checked, and 0.56 seems to work with notifications for me, however it doesn't work with call notifications. It looks like someone's broken the cmd field so all of them just say something like GB({"t":"call","cmd":"","name":"Test","number":"Test"}) now.

in the real world if I trigger notifications, it has some kind of inbuilt timeout?

It's probably Android power saving? I think you have to exclude Gadgetbridge from Android's battery management stuff