Without any warning, Google started rolling out Android 4.3.1 (JLS36I) late Thursday night. The first device to receive it is the 2013 LTE Nexus 7 (also known as deb and razorg).
At the moment, it's unclear what exactly the new features and bug fixes in this update could be, but it's worth noting that while Google has patched 4.3 in the past several times, this is the first 4.3 release to increment the version number.
The OTA weighs in at 9.42MB and has the same radio as 4.3 (DEB-G00_2.25.1_0802).
Several users have sent in the OTA urls for various versions of the firmware you may be updating (thanks, TheManii and Peter Kiddier!):
Flashing these is easy and should take just a few minutes using adb sideload.
Since I don't have an LTE Nexus 7, I couldn't grab the screenshots myself. Thankfully, several Japanese and French Twitter (Update: and now English-speaking) users have received the update and posted these:
If you have an LTE Nexus 7, go ahead and grab your update - perhaps you'll be able to find the differences before we do and let us know what they are.
Thanks, joey kache, TheManii, and others!