For many good reasons, Thales made the choice in 2013 to Open Source its field-proven, largely deployed, but proprietary modeling workbench Capella -- embarking all its enabling technologies such as Kitalpha, EGF, EMF Diff/Merge and Sirius in the process. The journey since that strategic decision has been a very challenging one, with no less than two tremendous transformations implemented simultaneously.
From 2008 to 2014, Capella has been developed internally in a closed environment, for known end-users, following a waterfall process. Since 2014, Capella is developed in full openness, following an Agile process.
Problems (big ones) were encountered. Challenges (ambitious ones) were faced and (often) tackled. Goals (not all) were achieved. Nearly three years later, members of the Capella development team are providing a feedback on this journey which saw them nearly square the circle. They explain how the transformation has been carried out, while still having to meet the strong expectations of Thales internal end-users and funders.
The adoption of Agile practices helped resolve open sourcing common pitfalls, the opened context helped develop external partnerships, manage third-party contributions, and share development guidelines.