CyanogenMod on Xperia Z1 compact: Amami or Yuga
You are running an unofficial build/port of the rom. If You must use official N build of the CM rom you should first change to official CM rom.
 You can't simply jump from some xyz rom( that's what UNOFFICIAL rom is) to official CM Nightly(N) or stable (Milestone, M) rom.
 Also if you are happy with your current non-CM rom, you may continue using them. You have to get updates for it from the developer whose rom you are using. Check for updates at XDA-Dev or whatever other development site from where you got your rom.
 If you wipe and load official CM nightly for your 'amami' you will be able to receive and install updates from CM.