I saw your message too late and had already upgraded DS-2CD2785FWD-ISZ from 5.4.6 to 5.5.3 . I detected another bug: when the alarm inport port changes its status (e.g. from close to open) one gets 20 emails (!) for each (!) alarm event. Is there any way to rollback to 5.4.6 or has HIKVISION...