The Graz Lagrangian (GRAL) system is a Lagrangian particle model with a free Graphic User Interface (GUI) available in both Linux and Windows. Now the developers have released the version 20.09. The software is open source under a GPL-3.0 license, so everybody is welcome to contribute to the project. The source code, has been published in github.
The version 20.09 of GRAL GRAMM has had some changes and modifications in the code, but focusing mainly in correcting bugs. No major features have been included in this update. See a list of issues solved here.