I tried looking around for a changelog but I couldn't find one anywhere (let me know if you know where it is, I know you can look at the commits/merged PRs on Codeberg but there's a lot to dig through).
Here's some of the changes I've noticed:
Profile picture next to username in top right
Comments can now be sorted by "top"
Larger image preview when uploading an image
Magazine stats are now localized (yay!!!)
kbin logo instead of stormtrooper in the "Create your own instance" box
Vote colors are brighter on dark mode
New theme: Tokyo Night
This is just what I've seen after using the site for a bit after the update, let me know if there's anything I've missed!
Edit: I just noticed that you can filter posts by language now, that's huge!
It's something that you wouldn't have seen unless you created a magazine (or community). In the magazine settings, there's a tab to view statistics like the number of posts, comments, and votes made per day. Before the update, all of the graphs were in Polish, so they were impossible to interpret without google translate. But now, they're properly translated into the language that you use