Sigma just issued this press text today:
Thank you for purchasing and using our products.
We would like to announce that we have confirmed that SIGMA’s interchangeable lenses for Nikon mount in the current lineup do not have any issues with general operation when they are used on the “Z7”, released by Nikon Corporation, via their “Mount Adapter FTZ”.
In addition, please note the information below when using the following lenses.
・Interchangeable lenses that do not incorporate an AF drive motor will operate only in manual focus.
・Some interchangeable lenses shipped out before November 2013 that are not compatible with the latest DSLR cameras will not operate.
We will continue verification and provide updates on the operating conditions including discontinued models.
For further information, please contact your nearest authorized SIGMA subsidiary / distributor.
We appreciate your continued support for our company and products.