There is one major thing in the 2.1 version of 480px which is a fix for a crash in the app review request portion of 480px. This error manifests itself as a crash when you try to launch the app. You should only see this if you meet all of the following conditions

1. You are using version 2.0 on a Windows Phone 8 device
2. You have launched the app more than 5 times.
3. You have launched the app on 2 different days.
4. You have not reviewed the app when prompted at startup.

A fix has been completed and submitted to the store.

This bug does not prevent lockscreen or tile updates from functioning properly.