Capcom detailed the patch note in a statement, it includes:
A generic filter to change the appearance of games, a colorblind mode with six new palettes for Super Puzzle Fighter II Turbo, a new difficulty option for Street Fighter II’ Hyper Fighting
Some bugs specific to certain games, in particular the speed modes which did not work, but also bugs in the online mode: the search function which finally works normally by selecting only one game, and the search for lobbies which now does appear those with a match in progress. Finally the sound problems, very common with the rollbackhave been corrected.
On the new side, it is now possible to leave a match after validation and return to it within a certain period of time. The always much requested opponent latency indicator has finally been integrated. It is now possible to make up to 10 rematches instead of 3.
Finally, several games have seen their training mode improved, with an infinite timer, a hitbox viewer which competes with Fightcade or now adjustable special resource selection modes. The detail can be found in the video presented by Capcom: