If you go treasure hunting in KOS, you should update to this, and you should also get the new treasure hammer from the dispenser in the blacksmith.
The new HerbalPotion is an item that you may find in a jar or you can buy from other player. It is an item type ‘vaccine’ and it will cure you from rat bites.
All the Items in the Jars have been replaced with items that will go to your game inventory. Once you find an item, you will be asked if you would rather use or sell that item, but then it will be stored in inventory.
This update is NOT mandatory.
PS: It also means that from now on, the alchemist skill item will be the Herbal Potion to be used on other people or to use on yourself.