Most of these are gonna be more akin to system wide changes than character specific:
Power-Up Abilities and X-Factor
Power-Up Abilities (Wesker No Glasses / Wolverine’s Berserker Charge / Devil Trigger / etc.) that provide a speed boost and/or damage boost will not stack with X-Factor. Only the bonus with the higher value will count (which is usually X-Factor).
Teleportation
The frames of teleportation remain the same. However, the image of the character at their teleport destination will appear sooner (To give the other player more time to notice where the opponent’s teleport destination is at. Teleportation is the strongest form of mobility in this game.)
High/Low & Left/Right Mixup Protection
(Credit to Skullgirls for the idea). If a character and an assist attack the enemy, the enemy is treated as though it is blocking high, low, left, and right at the same time for 6 frames after a hit. This protection only works if the attacks made within the 6 frame window were generated from two different characters. If a character made a high attack, then the same character made a low attack within 6 frames, the protection doesn’t work.
Vote to Change Less Popular Assists
During the month, Capcom compiles a list of least used assist moves for each character. If the percentage used is very lopsided (i.e., the assist move is only used 2% of the time while the other two assist moves were used 49% of the time), a poll will show up (in game or on the forums). The community then votes on what move the not-so-popular assist should change into and will be patched into the game.
Phoenix
When Phoenix dies with at least 3 bars of hyper meter, the player loses 3 hyper meter and Phoenix becomes Dark Phoenix. She stays as Dark Phoenix for 11 seconds (which is less time than her X-Factor Lv 1 duration). After the duration expires, she becomes regular Phoenix again, but with 1,000 HP, and she cannot turn back into Dark Phoenix again. The duration continues to count down even if she switches out. Because of this change, her life doesn’t drain as Dark Phoenix anymore.
Her Healing Field Hyper stops her Dark Phoenix timer from counting down while she is near the enemy. Healing Field Hyper now drains the opponent’s red life and heals Phoenix by the same amount. If there is no red life to drain, Phoenix won’t heal any life. Healing Field Hyper can now be performed in the air.