I checked out the raw v4.0.0. There are some differences: Sylvie's art design has changed a little, she has lighter colored hair and scars, slightly different scar positions, eyes are very different, and slightly darker nipples. That is not a exhaustive list, as I could miss any number of differences.
The closet has changed dramatically, much more varied color options and new clothes,
even preset color options. (as shown on the upper right side)
Last but not least, I hope this dispels the idea that this update is just clothes, there is a new sex position 'standing doggy', here are quite a few images of it and a new scene:
In case you didn't notice Sylvie is wearing a bra during sex. this counts far all positions. You can still remove it during or before sex, in the closet.
The last version I've played is 3.0.22. If any of this content has showed up in a earlier update, I missed it. This is only what I've found so far, not everything. There, that's a big post full of images to show off the content, took awhile but here you go.