I'm revamping the graphics on my first graphics asset pack: "Desert Dungeon". This asset pack has both animated sprites and regular tiles. I've read online that sometimes people like to buy sprites and tiles separately in case they only like one or the other. I'm also wondering if this would lead to an increase in sales if I assign a smaller price to the updated tileset pack and the sprite pack. 

However, a concern of mine would be if the people who have already purchased the old full version of "Desert Dungeon" would be able to download the new split versions for free. If this isn't possible, should I still keep everything together in one pack?

Last question: does Itch.io have a "newly updated" tab similar to the "new releases" tab? According to my analytics, this helped my visibility on Itch the most when "Desert Dungeon" released last summer.