In a sharded cluster, a view can only be read by sending commands to a mongos. You cannot connect directly to a mongod and issue queries against the view, even if all of the dependent namespaces of the view happen to reside on the same server. Users that attempt to do this will get a CommandOnShardedViewNotSupportedOnMongod error.

This behavior is accurate for all versions, so it would be nice to have this for both v3.4 and v3.6 documentation.

Scanning quickly through the views documentation, it might make sense to put a note about this in any sections that describe limitations of views (perhaps in https://docs.mongodb.com/manual/core/views/ under the "Behavior" section).