While many fans weren’t too receptive to Dragon Ball GT upon its initial release, it has sense gathered something of a cult following within the fandom, especially when it comes to Super Saiyan 4, which could mean that the widely popular transformation could be making its debut in the newly-established continuity of Dragon Ball Super in the near future–and if it does, GT already revealed the best way to make it happen. Upon the release of Dragon Ball Super, Super Saiyan 4–a transformation unique to Dragon Ball GT–became utterly obsolete. Super instead introduced a new level of power called Super Saiyan God.
https://screenrant.com/dragon-ball-gt-super-saiyan-4-introduce-super/