4k over coax

[organum]

I had 2 suppliers quoting to change recording equipment on a block of flats.
The recorders are all HikVision 2x16 channels for 32 in total.
I want to add 4 or 5MP cameras later to replace existing but one supplier says coax cannot support more than 1080P and the other says OK.
Assuming that the coax is in good condition and using compression like H264+ I would have thought that the higher resolution would be OK.
What does the panel think?

 

[RBW]

Hikvision Tvi 4K(8mp) cameras are readily available. Depends on the quality of the coax. Copper clad coax can give poor picture quality so pure copper is the way to go.