I installed yesterday iOS 8 GM on my iPhone 4s. Today morning when my iPhone rang to my surprise my Mac mini 2012 and my mid 2011 iMac started to ring. Since then all my calls are visible on all my Macs. iPhone's bluetooth is Disabled. All devices are in the same WIFI network. I haven't gotten any luck with continuity. I am running both mac mini and iMac on Yosemite latest DP. I sincerely doubt we will need bluetooth for the handoff.