OnePlus has started rolling out Oxygen OS 3.1.0 update for the OnePlus 2. The new update although still based on Android Marshmallow does patch the critical Quadrooter vulnerability.
Apart from that you have better Doze mode performance, the issues with Alert slider have also been fixed and you get the August security patch for good measure.
Although this is a welcome intermental update, most users are still waiting for VoLTE support to come to the OnePlus 2 as promised by the company. If you haven't received a notification on the update, just wait for a while more as the update is being rolled out gradually.
Source: OnePlus