From Sigma:
Firmware update for SIGMA 17-70mm F2.8-4 DC MACRO OS HSM | Contemporary in Canon EF mount
Thank you for purchasing and using our products.
We would like to announce that a new firmware update is now available for SIGMA 17-70mm F2.8-4 DC MACRO OS HSM | Contemporary in Canon EF mount.
[Applicable product]
SIGMA 17-70mm F2.8-4 DC MACRO OS HSM | Contemporary in Canon EF mount
[Benefits of the update]
·It has improved a rarely-occurring phenomenon whereby the recording stops during movie shooting when used with Canon EOS 80D.
[How to update]
Connect the lens to a computer via the SIGMA USB DOCK UD-01 (sold separately), then open SIGMA Optimization Pro*. If the lens firmware isn’t the latest version, the following message will appear: ‘The latest lens firmware is available’. Click ‘Yes’ to update.
* Before updating lens firmware using the SIGMA USB DOCK UD-01, please ensure you update SIGMA Optimization Pro to the latest version.
[SIGMA Optimization Pro download page]
https://www.sigma-global.com/en/software/sigma-optimization-pro/
Standard test results: Sigma 17-70mm f/2.8-4 DC Macro OS Contemporary Lens