A new update called Ultra Street Fighter IV was announced for release in early 2014 at the 2013 Evolution Championship Series. Before the release of the game, Capcom set up test locations to gather fan feedback that was taken into account for the final product.
The game was released in Japanese arcades in April 2014, later being distributed for home platforms as both a paid downloadable update for Super Street Fighter IV and Super Street Fighter IV: Arcade Edition, and as a standalone retail game. The update version for Xbox 360 and PlayStation 3 was released on June 3, 2014, with the full retail versions to follow on August 5. The PC versions (both digital and retail) are set for release on August 8, the PC port being delayed to get the console versions ready in time for the 2014 Evolution Championship Series. The PC version of Ultra Street Fighter IV will be the first game in the series to use Steam from day one, following the discontinuation of Games for Windows - LIVE.
The update introduces six new stages, and five new characters: Rolento, Elena, Hugo and Poison (all four of whom had been featured in Street Fighter X Tekken), in addition to Decapre, a member of M. Bison's Dolls, who makes her first playable appearance in the series. It has been revealed that, despite some of the new characters having been recently featured in X Tekken, their gameplay mechanics are substantially different in order to match the game's pace. The game also adds a feature called "Edition Select" which, similarly to Hyper Street Fighter II, allows players to select different versions of characters, based on their properties in past Street Fighter IV iterations. Also, the update adds a "Double Ultra" option, which makes both of the character's Ultra Combos available simultaneously, at the cost of them doing reduced damage.
Alongside the usual balance changes, the update introduces some new fighting mechanics. The first is a new move called Red Focus, similar to the regular Focus move, but having more invincibility hits. Also new is a "delayed wakeup" technique, which allows a knocked-down player to slightly lengthen the time before the character gets back up. Finally, based on fan feedback, the update removes all unblockable setups.
Source: Wikipedia, "Ultra Street Fighter IV", available under the CC-BY-SA License.