Investing in Open Source Software means to go beyond simply using it – it means to become an active member of the Open Source community. But how do we get there as a whole IT company? We decided that if we are going to take Open Source seriously, this needs to become deeply ingrained in the company’s and its employees’ “DNA” and in the way in which we create software. This is why and how we created the TSS FOSS Manifesto. The Manifesto is a set of guidelines which send our employees on their Open Source mission while having the company back them up. It is now a key pillar in how we become part of the Open Source movement, and we thus would like to share it with the rest of the world. In this talk, I want to present our Manifesto, the therein contained principles to drive forward the cultural change at Daimler TSS (and actually, perhaps all of Daimler), and their importance for modern IT companies.