The package has a debian/watch file, but the last attempt
to use it for checking for newer upstream versions failed with
an error:
In debian/watch no matching files for watch line https://gitlab.com/graphviz/graphviz/-/tags .*stable_release_(\d\S+)\.(?:tar\.xz|txz|tar\.bz2|tbz2|tar\.gz|tgz)
testing migration
This package will soon be part of the python3.12-default transition. You might want to ensure that your package is ready for it.
You can probably find supplementary information in the
debian-release
archives or in the corresponding
release.debian.org
bug.