You can import MIDI files to Guitar Pro and work with them in the default project, however the latest version does not save as .gp3 file, instead it uses a .gpx file. If you need a specific version of Guitar Pro project, you probably need to find that exact version of the program. In the case of midi to gp3 conversion you will most likely have to look for version 3 of the program.
Updated: May 22, 2020
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