Since 2.5 brings back empty jars, I no longer need to add them in this mod. In addition to XML changes (removed the added recipe, etc.) I also removed the custom icon and "hand item" that I made.
Additionally, polluted water follows the new setting for giving back an empty jar when drunk.
The changes are merged to the main branch, so re-downloading the file should get you the latest version.
You should not need to start a new game if you are updating from 2.4 to 2.5.