There are still modules which use 1.5, 1.6 or 1.7 and do not need that. The idea is to run jdeps on each artifact of a modul, add the relevant java.* and jdk.* modules to the dependencies of the module and upgrade to version 1.8. In a first change only none-jdk modules and none which depend on system dependency.
List in 2020-12-13_wildfly-22.0.0.Beta1-SNAPSHOT_modules_15_16_17.txt
Changes in a first set of modules in WildFly-Core WFCORE-5229 integration tests were successful.