Street Fighter V’s second season brought a significant number of balance changes to the game’s existing cast; despite this however, the data for season one still exists in the game’s code, mostly to allow replays from the previous season to still work, despite all the changes.
However, it seems that there is a way to play as the season one version of the characters–at least by accident. In a recent stream, Eduardo “PR Balrog” Perez experienced a glitch in an online match that reverted Balrog to his season one version. He noticed this after being unable to perform Screw Smash, which had its input changed to a dragon punch (forward, down, down-forward) in season two, from a charge motion in season two. You can check this out in these clips from PR Balrog’s stream below.
The exact method of invoking this glitch is as of yet unknown. However, the theory is that it happens when a player gets disconnected during the loading process before a match starts.
Source: PR Balrog via Adaptive Trigger