Microsoft today released a new build of Windows 10 Mobile to Insiders in the Fast Ring. The company is releasing Windows 10 Mobile Build 14342.1004 which is the same as Build 14342, but with additional fixes to improve the battery life which a lot of users reported about in this build. Microsoft stated:
We are releasing Build 14342.1004 today for Windows Insiders in the Fast ring. This build is exactly the same but with some additional fixes including a fix for the battery life issues we were seeing on some devices such as the Lumia 930, 929 and others which was also causing these devices to get hot.
If you are an Insider, you can get the latest build by heading over to the Settings app, click on Update & Security, and then check for updates.