Thanks to @dazulrich for pointing out the new firmware for -I NVR's on Hikvision's International site. As @Dan pointed out it is not available on the Download Portal.
The new version is numbered V4.51.005.
Loaded this morning on my 7608NI-I2/8P previously running V4.50.00 via the NVR web...
Found a new firmware update released for my 7608NI/I2-8P on the Hikvision RU and US sites. (Dated 2020/04/30)
I've used firmware updates from these sites previously on my world region NVR without any issues.
I've not had time to load the firmware and no release notes as yet. Would be great to...