Parallel replication agressive mode, why is 10.0.3 master needed?

Hi,

The documentation about parallel replication says at least MariaDB 10.0.3 is needed on the master. Enabling parallel replication in agressive mode does not work, as expected.

I don't understand why parallel replication cannot work when we put the mode to 'aggressive' . The documentation says no heuristics are used in this parallel replication mode. Therefor I think it should work with an old MariaDB (or MySQL, ftm) master.
If @@skip_parallel_replication is the reason not to support this I think a small note about this in the docs should be sufficient.

Let me know your opinion about this or if I missed something in my reasoning!

Cheers,
Michael