I was very annoid by the same volume for calls and notification. I tried several apps including "Notifcation volume unlink" xposed module and finally found the solution:
Its built GravityBox which I was using all the time, but didn't figuere it o...
Bug detected, exchange mail account crashing during configuraton (after setting up servers details) on default mail app
Present in all CM based N roms, use open gapps micro (google exchange/gmail).
Do anyone know, why i cant install twrp with cwm? It aborts with an error... Always
Because it is no flashable zip. Extract the zip and use flashify or sp flash tool.
I would like to flash V5.5 or V5.6. Unfortunately, the hoster is down. Are there any mirrors? If not, no worries. I can wait.
It's not complete down, you can reload the page until it works. I downloaded an hour ago.