The newer cumulative update should bring your devices to 14393.67, and contains a bunch of new fixes for Insiders to test. Microsoft is yet to post an official changelog, but once they do we’ll be sure to update this article.
The update is rolling out now, so if you’re an Insiders in any of the Insider rings, you should be getting this update now.
Update: Here are the changes
Addressed issue that causes significantly reduced battery life on Windows Phone when using Bluetooth with “Hey Cortana” feature enabled.
Addressed issue that prevents users from completing the out-of-box experience (OOBE) with a local account using Korean characters.