Arms has received a large update that makes myriad changes to the game, but doesn’t add any significant new content.
Wider changes include things like improved training and new exercises with difficulty levels, rush gauge changes, tutorials explaining elements of the 4-player mode, hotbox changes, and more. Every character in the game has also been balanced and changed. Some examples include increased dash speed for Master Mummy and “Improved curving performance” for the Megawatt. The list of changes is extensive, and you can find it here.
I really like the core combat and art style of Arms, but I am hoping a future update will offer some more encouragement to return to the game. Unlocking new Arms didn’t quite do enough to make me want to keep playing. I’m glad to see it is getting updates like this.