Mac OS Sierra 10.12.x
The premise is the same as shown for Mac OS 10.9.2 through 10.11.x except that the steps to enable the “Anywhere” option are different.
If you view your security settings under System Preferences | Security & Privacy, you will see there is no Anywhere option.
To enable the “Anywhere” option, run the following command in a terminal:
sudo spctl --master-disable
If you go back to System Preferences | Security & Privacy, you will see the Anywhere option enabled. Unlock the edit option by clicking on the padlock icon at the bottom of the window to change to Anywhere option.
At this point, you should be able to install the software.
This security setting affects your whole system. To reinstate the earlier security policy, run the following after the software is installed:
sudo spctl --master-enable
and then check your security settings are as you expect.