OFFICIAL PAGE: DeMIX Pro
DeMIX Pro, from AudioSourceRE, is an excellent application for upmixing mono source material to stereo. DeMIX Pro combines cutting-edge sound source separation capabilities with a built-in advanced spectral editor. Version 3 of DeMIX Pro now includes new improved All Vocals and Lead Vocal separation, new improved Bass separation, new improved Drum separation, high quality electric guitar separation, multi-track viewer, and faster separation times. In addition to harmonic selection capabilities, the built-in spectral editor includes a number of intelligent spectral editing tools. A multi-channel mixer is included which allows you to quickly and easily listen to your separations in the context of a stereo mix. Level, pan, mute, and solo controls are available for each separated track. DeMIX Pro performs its heavy number crunching in the cloud and is available for both macOS and Windows. Full details at the link above. Highly recommended!
Screenshots courtesy of AudioSourceRE