There is no way to revert back to the previous version  as with other platforms, and the FBX as it stands today is broken for DUF related expression export. I and a couple of folks have reached to to Daz only to get the runaround. Here's another customer who has been severely handicapped by the upgrade.

https://forum.reallusion.com/287158/When-will-we-get-the-DAZ-facial-pipeline-back-Latest-version-of-DAZ-has-broken-the-talking-character-conversion

I was brushed off and told "we will get our developers on this" after waiting 3 days for a response.  In my previous response, I asked for a link to the older version, a question I asked twice which was ignored.  SO, I have to wait another 3 days to maybe get the link after I asked for it again (3rd time)--meanwhile, an entire week will have gone by with  my inability to complete my project at this phase.  If you haven't upgraded yet, please do not until this is fixed, if it ever is.  Remember Daz customer service is not as good as reallusions.