CI is broken with last Jenkins upgrade.
Our agents still run under JRE 11, while Jenkins uses JRE 17 (Temurin-17.0.12+7).
This creates the following issue when the primary Jenkins server tries to launch the agent:
Caused by: java.lang.UnsupportedClassVersionError: hudson/slaves/SlaveComputer$SlaveVersion has been compiled by a more recent version of the Java Runtime (class file version 61.0), this version of the Java Runtime only recognizes class file versions up to 55.0 at java.base/java.lang.ClassLoader.defineClass1(Native Method) at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1017) at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:878) at hudson.remoting.RemoteClassLoader.loadClassFile(RemoteClassLoader.java:470) ... 23 more
That affects the PHP agent.
Checking rust_brown, Rust agent already uses OpenJDK 11. Those are based on jenkins-agent-barebone, already using OpenJDK 17.