Both .ms7 and .ms14 files are circuit designs from NI Multisim electronic schematic capture and simulation software, albeit from different versions of the software.
Thus ms7 to ms14 conversion is most likely searched by users that are looking for answer about the possibility of importing very old designs (in case of .ms7 files from version 7) to latest version of the software. This is usually possible, but not every legacy format might be supported forever.
In any case, only NI Multisim can help you with this and if you face particular problem or have specific issue, it may be best option to reach out to NI support for assistance.
Updated: January 5, 2024