Here are my steps to get Jriver to work in W2016 Core:
1. First partition your C drive into 2 partitions. We need dual boot. My M2 drive is only 128G, but big enough for both.
2. Install W2016 GUI in one partition
3. Then install W2016 Core in the other, then prep the OS like you normally would including applying AO 2.20
4. Now you have a dual boot system
5. Start GUI and install Jriver (I have tried Jriver 19 and Jriver 24, both worked) using the express method
6. Complete your license info
7. Restart GUI and make sure your Jriver license is still valid
8. Uninstall and now install a portable version of Jriver in a drive that is accessible to both GUI and Core
9. Complete your license info if it is not already there
10. Restart GUI
11. "Run as admin" and start "Media Center xx.exe"
12. Jriver should start as normal and your your license should be intact
13. Shutdown GUI
14. start W2016 core
15. Start Jriver (x:\jriver\media center xx.exe" in command prompt)
16. Your Jriver should work
This are the steps I get Jriver to work.
Hope you get it to work too and can enjoy the good sound of W2016+AO