We have a business that has become successful, the platform is a very customized build of Drupal where we integrate many different APIs and have a lot of custom code, mostly in PHP. Drupal and PHP are covered by the MIT license.
We talked to a lawyer and they said because it is the MITGPLv2 license if someone requests the code we have to give it to them, can we copyright any of this code? How can we protect it.
I know so many startups and platforms are written with open source software so I'm sure there is a clear answer to this but I can't seem to find one on the web.
EDIT We are using drupal which is the GPLv2 license.