Hi Joud,
Those classes are changed like below. If you have further problems, please share your code for review.
Unfortunately, we don't have a guide for such class changes but if you look at the commits (especially, unit test changes), it could be a hint how to change your app codes.
~~~
* org.drools.core.command.CommandService -> org.kie.api.runtime.ExecutableRunner
* org.drools.core.marshalling.impl.TimersInputMarshaller -> org.drools.serialization.protobuf.TimersInputMarshaller
* org.drools.core.command.impl.GenericCommand -> org.kie.api.command.ExecutableCommand
* org.drools.core.command.impl.FixedKnowledgeCommandContext -> org.drools.core.command.impl.ContextImpl
* org.drools.core.command.impl.KnowledgeCommandContext -> org.kie.internal.command.RegistryContext
~~~
Regards,
Toshiya