Abstract: Enhancements are now being made to the Gridpoint Statistical Interpolation (GSI) data assimilation system to expand its capabilities. This effort opens the way for broadening the scope of GSI’s applications by using some standard object-oriented features in Fortran, and represents a starting point for the so-called GSI refactoring, as a part of the Joint Effort for Data-assimilationI ntegration (JEDI) project of JCSDA.