Java APM agent for java 6

I am using latest ELK version 8.13 and I want to use elastic apm java agent to monitor Java application using jdk 6 as this app can't upgraded
Which agent version can be used or event refactored to be able to work

Sorry, we can't support Java 6, there is a core instrumentation dependency that only works on 7+. No version of the agent ever supported 6. Further bad news is that the OpenTelemetry agent is 8+ so you can't even switch to that