There is no python3-dask+diagnostics in the Fedora 35 repository. Hence, users who have python3-dask+diagnostics installed on Fedora 33/34 will experience a broken upgrade to Fedora 35 if the package name is not obsoleted. Once the recent commits in python-dask actually build, the package will show up and we will remove it from fedora-obsolete-packages. If this happens before final freeze, no further action is needed. If it happens after GA, the dasks's release number needs to be bumped to at least 2.