Currently spring-integration-test-support has hard dependency for the Log4j 1.x because of LogAdjustingTestSupport and Log4jLevelAdjuster. Since Spring IO doesn't provide Log4j 1.x support any more, we should consider to deprecate those components in favor of newly created based on the Log4j2. Also rework logging configs to Log4j2 as well.
Consider to remove those deprecated Log4j 1.x components in the next 5.1 version.
We still need to think how to exclude (or include?) Log4j 1.x matter from (to) Spring IO for compatibility.