I have a continuous contract with a single client for "IT services". I am developing a web application that is completely custom to their needs. As part of the agreement the application will be installed on the client premises and used internally in their company.
Some key points:
- The client will receive the full source code
- There is no place to "download/buy" this application for the public
- It is impossible for somebody else to buy this application
- The application is one of many delivered to the client as part of the contract.
Can I use the GPL version of the library in the application? Or do I need to buy a licence?