Cassandra upgrade from 3.11.3 -> 3.11.6

[Jai Bheemsen Rao Dhanwada]

Hello,

I am trying to upgrade from 3.11.3 to 3.11.6.
Can I add new nodes with the 3.11.6  version to the cluster running with
3.11.3?
Also, I see the SSTable format changed from mc-* to md-*, does this cause
any issues?