mviereck
Is this still maintained?
A new release needs to be issued, or at least installation instructions changed in the README.
The --update flag forces the installer to "update" to the latest release, skipping all bug fixes pushed to master in the last 2 years.
Using the --update-master flag instead resolves the problem.
The previous maintainer left two pinned issues at the top of the https://github.com/mviereck/x11docker/issues page. It sounds like someone would have to offer to step up and maintain it or fork the project. There are some outstanding PRs already but you could submit another with the README updates for what it's worth.
By the way, if you have any comments on https://github.com/mviereck/x11docker/pull/535, it might help to pave the way in case the maintainer does have time to check in on it.