(Bug filed by the maintainer.)

The Laravel Lumen framework has been abandoned upstream in favor of the
full Laravel framework [1].

Lumen 11 is the last version upstream and is based on Laravel 11.
The next version of Debian will most likely ship Laravel 12, which is
incompatible with Lumen.

I see no point in upgrading to Lumen 11 in the meantime. I will follow
up with an RM request once Laravel 12 is a certainty.

[1]: https://lumen.laravel.com/docs/11.x#installation