At the time of this writing (September 8th, 2016) Mac OS X 10.12 Sierra is still in beta.
UC 1.7.4 was released to support 10.11 and so far in our testing of Sierra is that yes the Firestudio and Classic 1394 Mixers should be working on Mac OS 10.12 Sierra with Universal Control 1.7.4.
If you have an older version of Universal Control installed from a previous OS such as 10.8, 10.9 or 10.10 and you're upgrading to 10.12 it will not work.
You'll need to uninstall it using our walk through guide then reinstall UC 1.7.4.
Apple has not yet released the final RTM version of 10.12 which is always different than the pre-release versions. As soon as we have qualified it look for a compatibility statement in our Knowledge Base Announcements area and on our forums for more information.
