AT&T Lumia 830 snags a firmware update

Lumia 830 users on AT&T are reporting a firmware update for their devices. The update brings change in the Firmware version but there is no impact on the OS version 8.10.15148.160 (GDR2) so it seems to be only a Firmware update pushed by Microsoft. The new firmware version is 2179.0.15455.24047 which is

Lumia Denim update not bringing new Firmware??

  This was brought to your notice by others too, but none of our device received the update in India yet. Now, a nicely done screenshot comparison of before and after scenario of the Lumia Denim update shows that Lumia 520 receives only the OS update to 8.10.14219.341 and firmware version