This build fixes some issues with r164, particularly that family instance variables were broken. The lag compensation system has also been significantly improved and now works slightly differently, so please review the 'Multiplayer: real-time game' example for the new way to use it. There have been some other reliability improvements to the Multiplayer system, including better connectivity robustness and fixes on the signalling server.
If you missed it, review the r164 release notes which introduced the Multiplayer engine.
Also today we reached 1 million downloads! To celebrate, if you download Construct 2 today (17th March) while logged in you'll be entered in to a free prize draw!