ZMD-DD-SBN8 Lots of questions

Ive had my unit for a number of years and updates to iOS 11 I think will cause me the loss of mobile access to my cameras away. I am pretty far behind in almost every way with this system and am not sure if I can keep using it, hence the many questions I have. Thanks in advance for anyone that can help:

  1. I have not updated my firmware in most likely 4 years. I dont have a display hooked up at the moment so I cant check what version I have, but know its not up to date. Has ZMODO updated the firmware for my unit?

  2. I am using NVMS 5 to view the cameras from my desktop computer - Im pretty sure this is old, but I am worried if I upgrade it wont work with my system?

  3. I have the Zviewer 1.0.4 app on my iOS and Android devices to view my cameras remotely. iOS is telling me this application needs to be updated to work with iOS 11. I have tried numerous other apps to view Zmodo cameras with no luck seeing my system. I installed Zsight and it cant find my DVR on my network so either I need a firmware upgrade or a different app. What options do I have for my system?

  4. If my system wont work with the newer apps/firmware, what DVR options do I have that will work with my analog cameras where I can get mobile access to view them?