Abstract: The CASTOR-K code is a hybrid magnetohydrodynamic (MHD)-drift kinetic code developed for the study of MHD modes in the presence of energetic ion populations. It allows a fast assessment of the linear stability of the modes, as well as an accurate calculation of damping due to thermal species (Landau damping). These capabilities make the code an invaluable tool for parametric studies and data analysis. In recent years, CASTOR-K has been mostly used to analyze JET data, including the identification of mechanisms involved in the expulsion of energetic ions from the plasma. However, in order to prepare the code to be used for a wider range of tokamaks including ITER, the code is being subject to a series of important improvements. These improvements aim not only to introduce new physics in the code but also to make it capable of exchanging data with other codes through its integration in modelling infrastructures. In this paper a description of the CASTOR-K code is presented, as well as a summary of the most important results obtained with this code and a description of the new improvements being implemented.