Like almost any app, Hikvision sends some data to it's own servers as well as third party analytics companies servers. What that data consists of I do not know. However, I can confirm the Android versions of iVMS-4500 and Hik-Connect I have used (I have only ever used Android app-store versions) do work communicating directly with your NVR/s if you connect directly to your NVR/s using the IP/Domain method.
e.g. I can block all app network access to any addresses apart from my own servers (using a firewall type app) and the apps continue to work.