For the record, Today I have update HWN-4208MH using firmware NVR_K74_BL_ML_STD_V4.30.085_210409 :D , from old buggy interface to new.
Fix ONVIF protocol to Chinese cameras.
PTZ OK
Alarm notification OK
All Things WORK.
NOT WORK:
UNBIND Recorder from other account.
SADP ERROR to UNBIND
Iphone...