Compared to the previous versions of the code, the additional new features implemented in the JOYCE3.0 procedure are generally aimed at expanding the base of potential users. This was done by providing interfaces for JOYCE3.0 with more QM and MD codes, and making parameterization more user-friendly for nonexperts. Nonetheless, it should be emphasized that the accuracy of QMD-FF stems from its specificity, and on the possibility to tailor in detail the FF description for each considered target. For this reason, although a preliminary automatic atom type assignment can be obtained using popular software and web servers, this assignment can be further refined by the user, allowing for the specification of user-customized atom types. To facilitate this process while providing sufficient flexibility and specificity, JOYCE3.0 now implements a four-subscript labeling system. Specifically, each atom composing the target molecule can take the label X abcd , where X is the atom name, and a, b, c, d are alphanumeric characters, which can be used to identify a particular atom type.