Included in the update is the support for new cameras including the Canon 650D/Rebel T4i, Fujifilm X-E1, and Sony DSC-RX100. The update also adds Album Support within the Revel Publishing Service and corrections for issues introduced in previous versions of Lightroom. There's also new support for a list of cameras including the Nikon D800 & Canon 5D MIII. Here's the full list of fixes and added support.
You can get the update by checking for Updates in the Help menu of Lightroom & Photoshop or download it from the Adobe Website.