Hi, when I change the version of drools from 5.3.5.Final to 6.0.0.Beta3 (maven pom) I'm getting following exception: org.drools.RuntimeDroolsException: Unable to load dialect 'org.drools.compiler.rule.builder.dialect.mvel.MVELDialectConfiguration:mvel:org.drools.compiler.rule.builder.dialect.mvel.MVELDialectConfiguration' at org.drools.compiler.PackageBuilderConfiguration.addDialect(PackageBuilderConfiguration.java:283) at org.drools.compiler.PackageBuilderConfiguration.buildDialectConfigurationMap(PackageBuilderConfiguration.java:268) at org.drools.compiler.PackageBuilderConfiguration.init(PackageBuilderConfiguration.java:181) at org.drools.compiler.PackageBuilderConfiguration.<init>(PackageBuilderConfiguration.java:159) at org.drools.compiler.PackageBuilder.<init>(PackageBuilder.java:210) at org.drools.compiler.PackageBuilder.<init>(PackageBuilder.java:143) at org.drools.builder.impl.KnowledgeBuilderFactoryServiceImpl.newKnowledgeBuilder(KnowledgeBuilderFactoryServiceImpl.java:34) at org.drools.builder.KnowledgeBuilderFactory.newKnowledgeBuilder(KnowledgeBuilderFactory.java:47) at net.javabeansdotasia.casestudy.test.Tester.prepareKnowledgeBase(Tester.java:136) at net.javabeansdotasia.casestudy.test.Tester.setUp(Tester.java:71) at net.javabeansdotasia.casestudy.test.Tester.main(Tester.java:160) Caused by: java.lang.ClassCastException: org.drools.compiler.rule.builder.dialect.mvel.MVELDialectConfiguration cannot be cast to org.drools.compiler.DialectConfiguration at org.drools.compiler.PackageBuilderConfiguration.addDialect(PackageBuilderConfiguration.java:278) ... 10 more would be nice if someone could help me, if the source code is needed let me know Andreas -- View this message in context: http://drools.46999.n3.nabble.com/ClassCastException-when-changing-drools... Sent from the Drools: User forum mailing list archive at Nabble.com.