YouTube updates its Android app to change the way the seek bar looks. The seek bar is the timeline with a button you can move to skip through parts of the video. With the 10.33 version, the button goes from white to a red ball. The bar seems to be thinner from the previous version as well. User interface-wise, there doesn’t seem to anything else introduced in the latest update. It’s currently available as an APK file over at APK Mirror. If you aren’t comfortable using APK files, the update should probably show up on your Android device soon.
Source: Android Police