The Jenkins documentation page,

"Upgrading Jenkins Java version from 8 to 11" needs updating since Jenkins 2.303.1.

If you use Docker containers to run Jenkins, you should follow the same process and change the Java version by appending -jdk11 to the Docker image tag.

Per blog, Docker images are now Java 11 by default. therefore the documentation should be updated to reflect the current state (ie: append -jdk8 to stay w/8).

Not sure if you want to retain notes for the intermediary states, or would just have submitted a PR myself.