It would seem dask.distributed has had a few releases https://github.com/dask/distributed/releases since March 4th when https://github.com/dask/distributed/pull/4460 was merged for Python 3.9 support? Time to support in Prefect? (https://github.com/PrefectHQ/prefect/issues/3453)

Hey Haf, we are unblocked by dask (and have been for quite some time) but we have not fully tested all of the extras that we support with Python 3.9 so we are not going to take the experimental label off yet. We are publishing docker images now for 3.9 though