From Sigma:
Thank you for purchasing and using our products.
We would like to announce that a firmware update for the SIGMA MOUNT CONVERTER MC-11 EF-E is now available. This firmware update makes the SIGMA MOUNT CONVERTER MC-11 EF-E compatible with the new product SIGMA 70mm F2.8 DG MACRO | Art for Canon.
* Before updating the MC-11 firmware, please ensure SIGMA Optimization Pro has been updated to ver. 1.4.1 or later for Windows, and ver. 1.4.0 or later for Macintosh from the following download page.
Applicable Product
Benefit of the Update
SIGMA Optimization Pro Download page
B&H carries the Sigma Mount Converter MC-11 EF-E.