With the current version of 6.4.4 on the desk phones, the new Voyager headsets don't have the ability to answer, hangup, or adjust volume using the BT700 in the phone. Updating the phones to 6.4.6 is reported to solve the issue. See the release notes from HP. There are also other fixes in this release.https://h30434.www3.hp.com/t5/Desk-and-IP-Conference-Phones/Software-UC-Software-6-4-6-was-released/td-p/8910203