Why are old rule files no longer working with the new Drools 5.3 in JBoss SOA-P 5.3.0?

Issue

We are trying to migrate to the SOA platform 5.3.0 I got an issue with my previous Drools files:

Here is the stack trace I got at the JBoss SOA-P server startup:

Caused by: java.lang.VerifyError: (class: com/jboss/soa/esb/routing/cbr/Rule_Routing_Rule___Can_ContinueEval0Invoker, method: equals signature: (Ljava/lang/Object;)Z) Expecting to find integer on stack
        at java.lang.Class.getDeclaredConstructors0(Native Method)
        at java.lang.Class.privateGetDeclaredConstructors(Class.java:2389)
        at java.lang.Class.getConstructor0(Class.java:2699)
        at java.lang.Class.newInstance0(Class.java:326)
        at java.lang.Class.newInstance(Class.java:308)
        at org.drools.rule.JavaDialectRuntimeData.wire(JavaDialectRuntimeData.java:413)
        at org.drools.rule.JavaDialectRuntimeData.wire(JavaDialectRuntimeData.java:400)
        at org.drools.rule.JavaDialectRuntimeData.onBeforeExecute(JavaDialectRuntimeData.java:241)
        at org.drools.rule.DialectRuntimeRegistry.onBeforeExecute(DialectRuntimeRegistry.java:132)
        at org.drools.compiler.PackageBuilder.reloadAll(PackageBuilder.java:1024)
        at org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:975)
        at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:455)
        at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:642)
        at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:41)
        at org.jboss.internal.soa.esb.services.rules.DroolsRuleBaseHelper.createRuleBaseFromRuleFiles(DroolsRuleBaseHelper.java:123)
        at org.jboss.internal.soa.esb.services.rules.DroolsRuleService.getRuleBaseStateForFileBasedRules(DroolsRuleService.java:245)
        at org.jboss.internal.soa.esb.services.rules.DroolsRuleService.executeStatelessRules(DroolsRuleService.java:99)
        at org.jboss.internal.soa.esb.services.rules.RuleServiceCallHelper.executeStateless(RuleServiceCallHelper.java:291)
        at org.jboss.internal.soa.esb.services.rules.RuleServiceCallHelper.executeRulesService(RuleServiceCallHelper.java:283)
        at org.jboss.internal.soa.esb.services.routing.cbr.JBossRulesRouter.route(JBossRulesRouter.java:135)
        at org.jboss.internal.soa.esb.services.routing.cbr.JBossRulesRouter.route(JBossRulesRouter.java:120)
        at org.jboss.soa.esb.actions.ContentBasedWiretap.executeRules(ContentBasedWiretap.java:202)
        at org.jboss.soa.esb.actions.MessageFilter.process(MessageFilter.java:65)
        at org.jboss.soa.esb.listeners.message.ActionProcessingPipeline.processPipeline(ActionProcessingPipeline.java:665)
        at org.jboss.soa.esb.listeners.message.ActionProcessingPipeline.processPipeline(ActionProcessingPipeline.java:612)
        at org.jboss.soa.esb.listeners.message.ActionProcessingPipeline.process(ActionProcessingPipeline.java:442)
        at org.jboss.soa.esb.listeners.ScheduleListener.onSchedule(ScheduleListener.java:117)
        at org.jboss.soa.esb.listeners.lifecycle.AbstractScheduledManagedLifecycle$1.onSchedule(AbstractScheduledManagedLifecycle.java:75)
        at org.jboss.soa.esb.schedule.SchedulerJob$ESBScheduledJob.execute(SchedulerJob.java:289)
        ... 2 more