After more then 2,5 years of development we have finally released a new major release of our OpenSource Content Management System build on top of Symfony. That’s a very long time, and we have totally underestimated how much work it will be. However, this allowed us to learn a lot of different lessons, from many different areas. Some concern how to plan such a project, how to handle certain restrictions or software architecture. In this talk I would like to tell you about as many as of these lessons as possible.