AMDV960H8 - Camera upgrade?

[big_onion]

I have an AMDV960H8, purchased the package with the 8 bullet cameras. This unit is mostly watching my barn so the lower resolution is fine, but I'd like to swap out a couple of cameras for something with a higher resolution. What cameras are compatible with this system? Will it work with anything as long as it's a BNC connection? I read in a few spots on here that the 960H can support other IP cameras -- is that accurate?