My instance has just upgraded to Lemmy v0.19.3 yesterday, but I don't see any of the new features (scaled sort etc). I tried logging out and back in (had to anyway as the subscriptions weren't showing). Switching to a different instance on 0.19.3 shows the correct features, but when I switch back, nothing.
I've just updated the flag, it may take a couple of hours to be detected by your app (or immediately if you clear app data)