While never called such in Dragon Ball DAIMA itself, Goku’s resultant furry, red-haired form, complete with a tail, is very reminiscent of Dragon Ball GT’s iconic Super Saiyan 4 form.However ...

Goku's Super Saiyan Blue (Universe Tree Power) fits comfortably among the latter. ... Super Vegito using his Spirit Sword in front of a shot of Super Saiyan 4 Gogeta from Dragon Ball GT.

If Goku had Super Saiyan 4 all this time, he had plenty of chances to show it off before Dragon Ball Daima 7 Times Goku Should've Used SSJ4 in Dragon Ball But Didn't (For Some Reason) Open Menu ...

Super Saiyan 3 Is Goku’s Strongest Form Right Now. Dragon Ball Daima is set shortly after the events of the Majin Buu arc, and before Beerus and Whis arrive during the Battle of Gods arc.

This is something that has been telegraphed for a while now but it now finally seems that Goku’s next level above Super Saiyan Blue has been revealed in a new episode of Dragon Ball Super.