i just want to run the client of Beta 1.7.3 and Exception in thread "main" java.lang.IllegalArgumentException: Unsupported class file major version 68 at org ...

I'm trying to run James 3.6.2 (Java Apache Mail Enterprise Server) using Espresso. I built the James project upon OpenJDK11, so I ran it with --java.JavaHome pointing to the OpenJDK11. However, I got ...