This updated technical paper compiles information on the mitigation and sustainable development benefits of actions, initiatives and options to enhance mitigation ambition, with a focus on the thematic areas of renewable energy and energy efficiency. Information for the update was provided in submissions from Parties and observer organizations and at the technical expert meetings held during the fourth part of the second session of the Ad Hoc Working Group on the Durban Platform for Enhanced Action, held in March 2014 in Bonn, Germany. This technical paper builds on the second version thereof, contained in document FCCC/TP/2013/8 and its two addenda FCCC/TP/2013/8/Add.1 and 2, and consists of the main document and an addendum. The addendum is focused on mitigation action in the thematic areas of renewable energy and energy efficiency and elaborates on mitigation potential, progress, benefits, costs and barriers, as well as on good practice policies, key opportunities and options for catalysing concrete actions in those two thematic areas