nextSIM-DG is a next-generation sea-ice model written in C++, developed as part of the Scale-Aware Sea Ice Project (SASIP). This poster documents our team's work on integrating the XIOS (XML input-ouput server) library into nextSIM-DG, giving it the ability to read and write to files in an asynchronous, parallel and efficient manner. Whilst XIOS is written in C++, its primary user base is the climate modelling community, who typically couple to it through a Fortran interface. We evaluate the benefits brought by this integration, as well as discussing the challenges associated with such coupling efforts. These challenges include implementing new backends within code bases of considerable size, deciding how much of the library to integrate, and coupling to codes in an unintended manner.