Every maven build I try to start on this just upgraded Jenkins-instance results in a stacktrace like:
Parsing POMs

[JMunin] $ /usr/lib/jvm/java-7-openjdk-amd64/bin/java -Dm3plugin.lib=/mnt/workspace/jenkins/cache/artifactory-plugin/2.1.7 -cp /mnt/workspace/jenkins/plugins/maven-plugin/WEB-INF/lib/maven3-agent-1.4.jar:/usr/share/maven/boot/plexus-classworlds-2.x.jar org.jvnet.hudson.maven3.agent.Maven3Main /usr/share/maven /mnt/storage/tomcat/jenkins/WEB-INF/lib/remoting-2.30.jar /mnt/workspace/jenkins/plugins/maven-plugin/WEB-INF/lib/maven3-interceptor-1.4.jar /mnt/workspace/jenkins/plugins/maven-plugin/WEB-INF/lib/maven3-interceptor-commons-1.4.jar 48878

<===[JENKINS REMOTING CAPACITY]===>channel started

channel stopped
ERROR: Het lezen van de POMs is gefaald.
java.io.IOException: Remote call on Channel to Maven [/usr/lib/jvm/java-7-openjdk-amd64/bin/java, -Dm3plugin.lib=/mnt/workspace/jenkins/cache/artifactory-plugin/2.1.7, -cp, /mnt/workspace/jenkins/plugins/maven-plugin/WEB-INF/lib/maven3-agent-1.4.jar:/usr/share/maven/boot/plexus-classworlds-2.x.jar, org.jvnet.hudson.maven3.agent.Maven3Main, /usr/share/maven, /mnt/storage/tomcat/jenkins/WEB-INF/lib/remoting-2.30.jar, /mnt/workspace/jenkins/plugins/maven-plugin/WEB-INF/lib/maven3-interceptor-1.4.jar, /mnt/workspace/jenkins/plugins/maven-plugin/WEB-INF/lib/maven3-interceptor-commons-1.4.jar, 48878] failed
at hudson.remoting.Channel.call(Channel.java:723)
at hudson.maven.ProcessCache$MavenProcess.call(ProcessCache.java:160)
at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.doRun(MavenModuleSetBuild.java:813)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:586)
at hudson.model.Run.execute(Run.java:1597)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:506)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:247)
Caused by: java.lang.NoClassDefFoundError: org/jvnet/hudson/maven3/listeners/HudsonMavenExecutionResult
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2451)
at java.lang.Class.getMethod0(Class.java:2694)
at java.lang.Class.getMethod(Class.java:1622)
at hudson.maven.Maven3Builder.call(Maven3Builder.java:117)
at hudson.maven.Maven3Builder.call(Maven3Builder.java:67)
at hudson.remoting.UserRequest.perform(UserRequest.java:118)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:326)
at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.ClassNotFoundException: org.jvnet.hudson.maven3.listeners.HudsonMavenExecutionResult
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
... 15 more
FTP: Current build result is [FAILURE], not going to run.
Finished: FAILURE

Before the upgrade, all builds where working fine but now they are all failing.