Hi maziyar, did you have a chance to look at this page: https://www.cloudera.com/documentation/enterprise/6/release-notes/topics/rg_cdh_610_incompatible_changes.html#incompatible_changes_spark ?  You're probabling hiting one of the incompatible changes mentioned there.   If that's not the case, then if ever you are using checkpointing in your Spark code and you are trying to run your code using existing checkpoint dirs created with Spark 2.3, then you may be facing the issue described here :  http://spark.apache.org/docs/latest/streaming-programming-guide.html#upgrading-application-code   You may need to cleanup your existing checkpoint dir or point to a new checkpoint dir as explained in that page.  " And restarting from earlier checkpoint information of pre-upgrade code cannot be done. The checkpoint information essentially contains serialized Scala/Java/Python objects and trying to deserialize objects with new, modified classes may lead to errors. In this case, either start the upgraded app with a different checkpoint directory, or delete the previous checkpoint directory. "   Eric ... View more