The definition of \Autoref uses \ltx@IfUndefined from the ltxcmds package. This assumes hyperref loads ltxcmds, which was recently removed as a dependency. It does still load ltxcmds implicitly through one of its other loaded packages, but in case one of those stops loading it it's probably better to change the definition of \Autoref to not use \ltx@IfUndefined.
The definition of
\Autorefuses\ltx@IfUndefinedfrom theltxcmdspackage. This assumeshyperrefloadsltxcmds, which was recently removed as a dependency. It does still loadltxcmdsimplicitly through one of its other loaded packages, but in case one of those stops loading it it's probably better to change the definition of\Autorefto not use\ltx@IfUndefined.