Not as of yet. If there is to be an upgrade released by Samsung is not been mentioned and I don't expect it. If anything it's most likely that a port of the OS will come from the hacker community however it's been said by Google that Android 5 Lollipop will run on much older systems with as little as 512MB RAM so it's not out of the question that it could make it's way to the S4 in a pure vanilla release straight from Google. Only time will tell.