We will present the developments done in the OASIS3-MCT coupler during the last 24 months to improve its parallel efficiency. The most important improvements concern the communication scheme, which now uses the mapping weights to define the intermediate mapping decomposition and the hybrid OpenMP/MPI parallelisation introduced in the SCRIP library for the mapping weight calculation. Efforts were also spent to improve the initialisation with the update of the MCT library from version 2.8 to 2.10.beta1 and to introduce new options introduced in the global CONSERV operation. Finally, additional results obtained with IS-ENES2 coupling technology benchmark, either testing new options or running on Marconi KNL, will be shown.