The MiMiC framework enables multiscale simulations by coupling external programs, which independently compute contributions belonging to different parts of a molecular system. We refer the reader to our original presentation of MiMiC in Ref. 1 for a more detailed description of the framework itself. Here, we provide some details relevant to the MiMiC-based QM/MM implementation in which CPMD and GROMACS are used to enable QM/MM MD simulations. In this implementation, the CPMD program serves as the main MD driver and additionally computes the QM contributions while GROMACS provides the MM contributions. The MiMiC framework itself is built around a multiple-program multiple-data (MPMD) approach with loosely coupled programs. This allows the external programs to run simultaneously and independently of each other with periodic data exchange, which relies on network-based solutions rather than file-based data exchange (further details are given below). Moreover, it enables separate allocations of processor pools to each of the programs, thus allowing each program to utilize its own optimal parallelization scheme which improves the parallel efficiency of the resulting solution.