I searched about this but couldn't find a case close enough to my current circumstance.
I developed a tool which I sell online which contains compiled python code inside. The tool is used to submit visual effects renders to the render farm, so its intended us is to help the production of commercial visual effects work.
Out of goodwill I let my former employer use the tool free of charge when I was working there and renewed their license on an annual basis free of charge twice. No definition of license was ever discussed.
I've been asked this week if I could sell my former employer the source code as they would like to maintain it internally.
I'd like to maintain full ownership of the tool and source code and just provide my former employer the ability to edit it and use as long as they keep it internal to the company. Under no circumstances the tool (and source code ) should ever leave the company, be lent, given, sold, advertised, passed to third parties or remote workers etc. The only damage I would get from this is if the former employer or any employee was to try to sell it online and compete with me.
I think I can build a license agreement from scraps of licenses found online.
However I'm confused as to whether I would need to grant the right to do derivative work.
I guess the question would be: would editing and updating the source code (to be used internally and not to be included or resold) be consider derivative work?
Thanks for your help Pep