From Sigma:
Thank you for purchasing and using our products.
We would like to announce that we have updated the firmware of the SIGMA Optimization Pro, the dedicated software for the SIGMA USB DOCK.
The latest firmware enables our Nikon fitting interchangeable lenses fully functional with the Nikon D5300 camera. For those customers who own following products, please update the firmware of the lens via the SIGMA Optimization Pro.
Please update SIGMA Optimization Pro Software to Ver. 1.1 before attempting firmware update.
You can download the latest version of the software from the following page:
http://www.sigma-global.com/download/
Adorama carries the Sigma USB Dock (necessary to upgrade firmware).