Drupal displays messages to the user about the security support status for the currently installed Drupal minor version. Usually, the security support lasts for two minor releases (e.g., Drupal 9.2 is supported until Drupal 9.4.0 is released.)
However, for the last two minor versions of the series, the end-of-life dates must be hardcoded, since there will not be two more minor versions. This is implemented in an internal class in Drupal\update\ProjectSecurityData
with class constants.
In Drupal 9.4, the constants for Drupal 8 are removed (since they are dead code on 9.0 and above), and new class constants are added for Drupal 9 versions. The constants should not be used outside core and should not be used on any Drupal version other than the one in their name, so there is no backwards compatibility break and no continuous upgrade path is provided.
Added
const SECURITY_COVERAGE_END_DATE_9_4
const SECURITY_COVERAGE_ENDING_WARN_DATE_9_4
const SECURITY_COVERAGE_END_DATE_9_5
const SECURITY_COVERAGE_ENDING_WARN_DATE_9_5
Removed
const SECURITY_COVERAGE_END_DATE_8_8
const SECURITY_COVERAGE_ENDING_WARN_DATE_8_8
const SECURITY_COVERAGE_END_DATE_8_9