gp5 to gp conversion is most likely searched by users that are looking for ways or options how to convert or resave different versions of Guitar Pro. As a general rule, the latest version of software usually saves to latest format only, with few exceptions being the previous version only. So modern versions of Guitar Pro will save your files as .gpx files, which means that if you are looking for particular version of the files, you have to obtain particular version of the software. Maybe abandonware websites can help.
Updated: October 4, 2023