Issue #2281697 by benjy, Ryan Weal, oadaeh: Fixed Field weights are not migrated.
Issue #2281591 by benjy, Ryan Weal, vendion: Author information does not migrate over.
Issue #2326881 by tim.plunkett: Convert filter_element_info() to Element classes.
Issue #2281553 by benjy, Sutharsan, ultimate: D6->D8 Node Revision migration is incomplete.
Issue #2325185 by dawehner, tim.plunkett: Convert views_element_info() to Element classes.