Hi all, for deploying our rules we usually create packages in Guvnor and then deploy the .pkg binaries to our application where we access them via a change set file, e.g. as a classpath or url resource. We have also used the Drools Ant task to create packages directly from the rule sources in Eclipse, cause it would be convenient for testing and development purposes to be able to just drop that file in place of the one created from Guvnor. However it seems that the KnowledgeAgent can't read the pkg format produced from the Ant task, we get an Exception as follows: java.lang.RuntimeException: KnowledgeAgent exception while trying to deserialize KnowledgeDefinitionsPackage at org.drools.agent.impl.KnowledgeAgentImpl.rebuildResources (KnowledgeAgentImpl.java:418) at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet (KnowledgeAgentImpl.java:120) ... Caused by: java.lang.ClassCastException: org.drools.reteoo.ReteooRuleBase at org.drools.agent.impl.KnowledgeAgentImpl.rebuildResources (KnowledgeAgentImpl.java:413) We are using the same drools-core.jar for building and running so I don't think this is a simple class version mismatch. Has anybody got a similar scenario working? Any clue what we might be doing wrong? (We are using Drools 5.0.1.) Thanks, Gerret