Today, Super Smash Bros. 3DS version is released in North America and Europe with the first day of the patch and the two newest trailers.
You can get the patch download instructions here: http://en-americas-support.nintendo.com/app/answers/detail/a_id/11692/p/430.
This patch is required to be downloaded because it will enable the multiplayer features in this game. In addition, these patches also provide adjustments that make the playing experience will feel better again.
Nintendo has also released a new trailer and "how to" video that you can see below.
