It’s very normal for Nintendo to release updates for their Switch games. Most of the updates they release are usually for games that released in the past few years. However, once in a blue moon, they’ll give the Switch games they released in the early years of the console’s life some attention.
This is no exception. Nintendo has released an update for Super Mario Maker 2. Once you update, the game should be at version 3.0.3. Unfortunately, the patch notes are very small. In fact, all Nintendo says is that they “made adjustments to make for a more pleasant gaming experience”.
Source
Related
mynintendonews.com