The Standard Support end date for ThingWorx Platform versions 6.5 and 6.6 will be October 1st, 2018. Developers utilizing those versions are encouraged to upgrade to the latest version of the ThingWorx Platform.
Please reference the Customer Support article ThingWorx 6.5 and 6.6 notification for standard support end date for further details and for information on how to leverage PTC Technical Support for any questions.