https://wccftech.com/super-mario-maker-2-update-3-0-0-notes/

Super Mario Maker 2 Update 3.0.0 is currently being rolled out for the Nintendo Switch and we’ve got you covered with the full release notes.

As covered yesterday, the new free and final major update for the game adds the new World Maker Mode, all of the seven Koopalings, new course parts and new power-ups from previous Super Mario games. The new World Maker Mode in which players can tie together multiple user-created courses. The look of the world map can also be customized. Up to eight worlds containing a total of up to 40 courses can be combined, creating a mini Super Mario game that can be shared with others.