Upgrades can increase the power of a character's Special Attacks or Super Move. Spare upgrade cards can be obtained in booster packs that usually give one random character and two other contents (support cards and upgrade cards being the possible results of the latter). Players cannot choose to upgrade a Special and/or Supermove with Power Credits if they already own a spare upgrade card, the cards must be used up first.
Also noted, if you receive an upgrade card for a character's SP1 and Supermove, they can be used for ALL versions of that character irregardlessly (the ONLY exception being Harley Quinn, since each version of her have the same SP2 as each other, yet have different SP1s for other versions); for example, if you receive an upgrade card for Batman's SP1, you can use it to upgrade the SP1 of ANY VERSION of Batman, no matter which one it is.
Upgrade cards can be sold in the Store for 30% of the cost to upgrade it without the card. If viewed in the Collection, the entire list of one's owned spare upgrades will be displayed (and also the number of each card owned).
- Whenever a new update occurs, the upgrade cards for a new character will usually be released into packs before the character is ever released. For instance, the closest case that this has happened was for Solomon Grundy/Earth 2's, as his SP2 upgrade card could be pulled from packs as soon as the 2.9 update was added, but the character was not added into the game before the 2.11 update.