The latest release of RMG includes updates across all three components to expand modeling capabilities and improve accuracy, robustness, and performance. RMG uses a core/edge reaction model during mechanism generation, where the core contains species and reactions which have already been identified as being important, and the edge contains species and reactions which are under consideration. To reduce the model truncation error, in each iteration, RMG identifies one or more species to move from the edge to the core based on the species' total formation rate in a homogeneous batch reactor simulation. It then generates new reactions between the newly added species and other species in the core. The model is considered converged when no edge species exceeds the user-specified tolerance for selection.