Firmware Version: v1.10 7/30/2012Revision Info:-Enhanced Stability.
-Updated DDNS UI.
-Improved wireless performance.
DIR-615 Rev ANOTE: If your router is working with out any issues, it's recommended to keep the current version of FW that is loaded.IF IT WORKS, DON'T FIX IT!!! 
Do
NOT upgrade firmware on any D-Link product over a wireless connection.
Failure of the device may result. Use
only hard-wired LAN network connections.
Please follow the (link)>
FW Update Process for upgrading.