In the past decade, we have witnessed an increased interest amongst commercial and public sector organisations for Open Source Software (OSS). As any individual and organisation has the right to freely read, use, improve and redistribute the source code for software that is developed and released under an OSS licence, it creates new opportunities for Open Innovation. In this chapter, we report on how companies collaborate on production of software artefacts in an OSS project, thereby showing how a form of Open Innovation can be utilised by a large company that goes beyond collaborative development of ideas. In doing so, we report on company decisions and development practices concerning how a software project evolved from proprietary to an open collaborative software development project that is released under an OSS licence (LGPLv2).