Its been experimental for a while and can be enabled manually via some properties changes.
It also looks like crap, they render at a lower res and scale up a bit poorly. I settled on just making my fonts scale fractionally and it looks better IMO.
Were you running X11 apps? I think there's issues with low res on X11, but Wayland apps should be running at integer scaling and then scaling down to whatever fractional scale you've set it to.