Activation on Development and Staging environments
License activation is not required for the plugin to work - it does not limit the plugin functionality in any way. It is only used for the automatic updates script for verification.
The updater script in some cases allows simultanious activation of the license code on development and staging environments. This is possible, if:
  • the sites reside on the same IP address
  • the development or staging site is on one the following subdomains: dev., staging., members., test., ww1, ww2, 1., 2.
For example, if you main site URL is yoursite.com, then dev.yoursite.com, staging.yoursite.com, test.yoursite.com etc.. should be allowed to register the same purchase code.

I can not activate on the staging or development or live site simultaniously, what should I do? Which should I activate?

In that case, you can still use manual updates.
If the development or staging sites are deployed to the live environment, then it is sufficient to enable the automatic updates only on the one, that is directly deployed to the live environment - if the deployment process overwrites the files and the database as well.