I upgraded my DS-2CD2355FWD-I to V5.5.83 build 190221, I can now see HTTP Listening added to the Network advanced menu. I believe it can now be used as webhooks, presently I'm doing it with rules using the Synology NAS to interface with smart home system. I tried entering JSON URL in the URL field, saved it, tested it and it did not work. Now when I return to this menu, the table to enter IP/URL detail is gone, it gives me error "Network is disconnected", pressing the default does nothing. I guess this is initial implementation and has bugs. I would love to hear, if someone has used webhooks as alarms directly with Hikvision cams.