After several years of silence, Principia has finally been released as open source. With this comes new development and a Linux version.
The source code is available on GitHub and is free for anyone to modify and submit pull requests to. Check out the 1.5.2 roadmap for the current progress on the first open source version that is being developed.
In addition a new community site, principia-web, is available. Originally an unofficial community replacement hosted by ROllerozxa for the past two years, it has now become the primary community site for the open source Principia. The game is also able to connect to other community servers however, such as the Official Community Site Archive which is a complete archive of the old community site's levels.
For more info, see the news post on principia-web. Be sure to also join the Principia Discord server to stay up to date with the latest developments.
