Hi! I really struggled some time with serialization issues: I want to create a pkg and package that with the jar. From there I want to read it during runtime. Easy I thought. Drools 5 way should be to serialize the KnowledgeBase, right? At least, this is what the AntTask does. If I try to serialize the KnowledgePackage I get an excpetion anyway: Okay. Back to the KnowledgeBase. Serialized with Drools 5.0.0.M4 and try to read it with 5.0.0.M5: Caused by: java.io.InvalidClassException: org.drools.impl.KnowledgeBaseImpl; local class incompatible: stream classdesc serialVersionUID = -4540376767025107954, local class serialVersionUID = -3186110098262381425 So it seems Drools Packages are NOT compatible between minor versions? This would be a disaster for deployment. Or do I serialize the wrong thing? Unfortunately I didn’t find anything in the docs about it. Then I tried to do it the “old” Drools 4 way and serialize Package objects, but same problem with a different serialVersionUID! Why do these important classes don’t have a serialVersionUID? Or how should that be loaded? Must be a big issue with Govner, so I think there must be a solution already? Thanks for any help! Cheers Bernd