31 organisations are publishing an open letter. The letter calls for lawmakers to advance legislation requiring publicly financed software that has been developed for the public sector be made available under a Free and Open Source Software licence. Digital services offered and used by public administrations are the critical infrastructure of 21st-century democratic nations. To establish trustworthy systems, government agencies must ensure they have full control at the core of our digital infrastructure. Unfortunately, this is rarely the case today, due to restrictive software licences.