ns-3.20 was released on 17 June 2014. This release features a new LR-WPAN model providing initial support for IEEE 802.15.4 networks, and integration with the previously released SixLowPan (6LoWPAN) module. A new IPv6 routing protocol (RIPng) model has been added, and support within the Flow Monitor for IPv6 has been added. A new LTE MAC downlink scheduling algorithm named Channel and QoS Aware (CQA) Scheduler is provided by the new CqaFfMacScheduler object. In addition, the RELEASE_NOTES list the many bugs fixed and small improvements made.