It’s been available for some time. I think whomever packaged 4.11 though forgot to include it, but you can always get it on github:
(if you haven’t already, you’d need to link your Epic ID and github accounts. https:///ue4-on-github
I’ve also had it on dropbox for some time, but github is guaranteed to have the latest. Dropbox - ArtToolsOSX - Simplify your life?