The Graz Lagrangian (GRAL) system is a closed-source Lagrangian particle model with a free Graphic User Interface (GUI) available in both Linux and Windows. This model has a special module focused on odour dispersion modelling and now, a new beta release has been distributed in the mail list of users, with an extensive list of changes.
People interested in testing and trying this new beta, should subscribe to the official website of the project here. The current version 19.1 has been updated to the version 20.1. According to the release notes, this is the third beta of this version. There is no information on when the final version will be released.