Just in case this is useful to anyone:
Upgrading my 2042 and 2142 cams to 5.5.0 broke some functionality for me as well...
1) my custom integration with domoticz (uses nodeJS to read the alertstream and sends that to domoticz using mqqt)
2) event messages in hik connect (the "notify surveillance center" option)
I got domoticz integration back working by re-enabling hikvision-CGI and setting authentication to digest/basic
Configuration/Network/Advanced Settings/Integration Protocols/Enable Hikvision-CGI - set to digest/basic
In an attempt to fix the connection to hik connect, I also tried changing other settings back to their pre 5.5.0 (less secure) status
Configuration/Network/Advanced Settings/Integration Protocols/Enable ONVIF
Configuration/System/Security/Authentication/RTSP and WEB authentication to digest/basic
It did however not solve my messaging problem in hik connect... this is still dead in the water... but it may help others with their integration issues.
I had to reboot/disable H264+ to see the face detection event option and tweaked the video settings.
Image quality seems better then before.
Everything else seems to work.
Quick update to this:
Hik-Connect issue is also fixed after tweaking the Device settings in the Hik Connect App.
Device List / Edit Device / Settings -> Set alarm notification back to Enable and fixing device timezone information. This was off again after the upgrade.. :-(
So for my devices everything is back working fine.