Not every single art from previous updates will be reworked. By "old art" we mean art from 2020-2021, when the game had just started and our current lead artist wasn't as experienced as he is today.
As a matter of fact with 1.8 we're mostly done with reworks besides very few things like backgrounds or Evelyn's stuff (those artworks are also from that 2020-2021 timeframe) which we have decided not to rework until we rework her entire route.