The following files in jenkinsci/packaging assume that we support both Java 8 and Java 11.

templates/base.html
130:              <li>2.164 (2019-02) and newer: Java 8 or Java 11</li>
131:              <li>2.54 (2017-04) and newer: Java 8</li>

templates/header.war.html
16:  <li>2.164 (2019-02) and newer: Java 8 or Java 11</li>
17:  <li>2.54 (2017-04) and newer: Java 8</li>

This assumption will no longer be valid once we start requiring Java 11. To adapt to the new reality, a new entry should be added to both of these lists for whatever 2022 release of Jenkins begins requiring Java 11.

Note that a perennial issue with documentation for major changes is that jenkins.io covers both weekly and LTS releases. This makes for an awkward period when the major change has landed in weekly but not yet in LTS. Choices are:

• Revise the documentation to describe both weekly and LTS, then revise it again when the major change ships in LTS. (Ideal, but the most work.)
• Revise the documentation to describe the major change when it has shipped in a weekly, accepting that the documentation will be off for LTS users for a few months. (Not ideal, but probably good enough in many cases.)