As part of the Anubis effort (T400229), we're building new VMs running Debian Bookworm, which gives us PHP 8.2. That in turn invites us to upgrade Symfony.

Our current Symfony version, 5.4, will reach EOL in February 2029 (roadmap). So the Symfony upgrade is not a requirement, but it is already quite old. I think the goal should be to aim for Symfony 7.3, which will allow us to easily upgrade to the next LTS release, 7.4, once its ready.

See the docs on upgrading to a major version.