Every now and then I stumble across some more or less cool application I install on my Mac. Some of them were built by authors not verified by Apple. Whenever this happens you see a box popping up telling you that you can’t run that app. You can go to the security / Gatekeeper pref pane and allow for this app for this time to run but the option just to allow all unverified apps to start is gone since 10.11 I suppose.
Since Apple very seldom removes a functionality from a new release there is a way to switch to allowing those apps from the command line. I found a solution on the german Mac site MacGadget:
sudo spctl --master-disable
This works just like to old option setting. HTH.