Did the update and checked into our 4.12 releases branch, not sure how it works to getting out in previews, will ask. That link should work to download. To do the upgrade locally, just copy the ovraudio64.dll, OVR_Audio.h, and ovraudio.link64.lib in that zip file over the ones in the UE4 source code and rebuild the Oculus Plugin, then it should be working with new version.