The bigger brother of Samsung's super-premium tablet offerings has already been blessed with Lollipop on AT&T, so now it's the smaller version's turn. Galaxy Tab S 8.4 owners on Ma Bell should be getting an Android 5.0 over-the-air update starting today, at least according to AT&T's support page. Technically it's Android 5.0.2, but who's counting?
Effective June 16, 2015, AT&T has released a software update for the Samsung Galaxy Tab S 8.4 (SM-T707) . This update will be made available to customers via the Firmware Over the Air (FOTA). A Wi-Fi connection is required.
Android 5.0.2 Operating System update which includes Lollipop 5.0 and the additional enhancements.
"Quick Settings" updated
What to expect after the update
Although there should be no impacts to settings or data, we recommend that you back up your media files to an SD card, a PC, or using a favorite application (from the Play Store), prior to upgrading the software.
AT&T's software changelog doesn't mention anything that isn't included by default with Lollipop, but it does say you'll need to connect to Wi-Fi to start downloading the update file, as usual. But considering that the file is over 1.1GB (no, Samsung's really not getting any better at this), maybe that's not such a bad thing. It also means you'll need at least that much free space on your tablet before finishing the download, so delete some of those games.
As with all over-the-air updates, any significant software modifications may cause a flash failure, and don't be surprised if it takes a week or more for AT&T's slow rollout to reach your specific tablet. Unfortunately SamMobile doesn't have a firmware entry for AT&T's specific model (SM-T707A), so you'll have to wait for the OTA alert or start hunting on user forums for a manual download.