Question: I want to mirroring from Kafka Source Cluster to Kafka Destination Cluster. Everything is working fine if my both Source and Target Cluster are on the same version (say 0.10.0.0) but its not working when my Source Cluster is on 0.8.2.1 and Target Cluster is on 0.10.0.0.

Does anybody have any idea?

Thanks in advance.

Answer: 
I'm encountering this same issue. It appears that the mirrormaker is only works if the source and target clusters are the same version.
I got it to work by using the mirror tool of the old version to consume from the old version and to produce messages on the new version. Vice versa does not work. That was between a 0.9 and a 2.7 version though.