Music XML 4.0 in Dorico 4?

Does Dorico 4 support MusicXML 4.0?

Not yet. You would have to configure Finale to export XML 3.x

I seem to remember exporting Finale files in a later version of XML than Dorico officially supported at the time, and it still seemed to work most of the time. Has anyone experimented with this yet?

There should be no problems opening MusicXML 4.0 files in Dorico 4, but Dorico does not support any specific MusicXML 4.0 features.