Seems that Sprint is starting it's push of both the M8 & M8 HK version of Lollipop...
http://support.sprint.com/support/a...your_HTC_One_M8/WServiceAdvisory_542_GKB69195
http://support.sprint.com/support/a...your_HTC_One_M8/WServiceAdvisory_542_GKB69195