"During 2003 Star Air and UPS entered into a new contractual agreement for the next 10 years. From 2005 Star Air gradually placed 11 Boeing 767SF (Special Freighter) in service with UPS. The 757PFs was returned to UPS."
http://en.wikipedia.org/wiki/Star_Air_(Maersk_Air)
Granted, you cannot trust Wikipedia all the time, but that artical suggests the contract is up next year 2013.