The Catholique University of Louvain (Université catholique de Louvain - UCL)decided to rewrite their core business applications from Java/EE toPython/Django and make them freely available as open source software. Thispresentation intends to share with the community the experience on buildingOSIS, the open source transition, the cultural and technical shift, theengagement of students, teachers and employees on the improvement of their ownuser experience, the costs implied and the productivity gains. OSIS (Open Student Information System) is an application designed to managethe core business of higher education institutions. It is free and open sourceunder the terms of GPL v3 public license, aligned with the strong spirit ofknowledge sharing and collaboration with the community. The project issponsored by [Université catholique deLouvain] (UCL) in the context of its long termgoal of modernising its information systems towards the next generation ofstudents, devices, practices and technologies. We aim that UCL and many other higher education institutions adopt OSIS to beable to maintain, control and monitor the entire student’s career. Thisextends from the admission to the diploma and all information orbiting thisfundamental process, such as planning the academic year, managing partnershipswith other institutions for exchange and mobility programs, assigning teachersto courses and courses to students, etc. At the current stage, OSIS isdesigned to fulfil UCL’s needs, but it can be properly adapted to fulfil moreneeds coming from other institutions interested in joining the project, whichis the case of Université Saint-Louis, Bruxelles. For us, offering a reusable system is not the only advantage of being opensource. It also means: * fully transparent operations for the entire academic community; * inspiration for entrepreneurs to build integrated services to improve students academic experience; * empower departments, endowed with the necessary expertise, to fulfill their particular needs by extending OSIS; * build up students' experience on real world projects to boost their chances when applying for a job or founding a company; and * reduced maintenance cost for the University thanks to the range of reliable open source products required by the application. But the path to open source was not simple. It required lots of discussions tofinally find a realistic long term formula to meet the institution's majorgoals. Now that it is our reality, this history cannot be kept aside, butshared with FOSDEM's community. We are going to answer the following questionsduring the presentation: * Why we are sharing our core business applications before any other higher education institution. * How the academic community persuaded us to use Python/Django/PostgreSQL instead of JavaEE. * How we are adapting to this new reality that requires much more discipline and high quality craftsmanship work. * Why there is no doubt we will succeed in this entrepreneurship. * Why we need your help to better manage and write this open source software.