It's the update that Nintendo introduced with the new "welcome amiibo" characters, basically some of the returning villagers from past games. A whole bunch of new furniture was added as well as some other features, including the fact that villagers no longer plot on paths/qr patterns. You can still play without the update, you just can't wifi with anyone anymore until you update. It's worth it though :>
Yeah, you can scan in amiibo cards and make them move to your town, and you can use amiibo figures also to make them go to your campsite which is a new addition. x