Thanks for contacting us! We have tested with Sierra and there doesn’t seem to be any new issues with it. The original issue with saving in Safari on El Capitan also appears in Sierra however the fix we implemented for El Capitan is also working for Sierra. There are therefore no known issues with this Mac OS upgrade.
In the unlikely event that you did experience any issues after upgrading, these could be worked around by using a different web browser than Safari, such as Chrome or Firefox, however based on our tests you shouldn’t see any issues.
Let us know if you have any further questions.