Let's consider following scenario:
- Person A creates a piece of software and releases the source code under a permissive license, let's say MIT
- Person B downloads that piece of software and uses it accoridingly to MIT license.
- As an owner and holder of all the right Person A decides to change the license from MIT to other license, especially less permissive one like GPL. For simplicity let's assume that there were no contributions to the piece of software in the meantimy by any other people.
- Person A releases a new version of the software
In that scenario what happens to the rights given to the person B?
- Is person B allowed to still use the last version released before the change of the license under the old license (MIT) and all the versions released after change of the license as new license (GPL)?
- Is the entire piece of software licensed MIT or GPL after the change?
- Basically can rights given by license be revoked by the owner?