The FCV 4.4 checkShardVersion protocol is, when the shard does not have a shardVersion cached for a namespace:

• if the namespace is a collection, the shard returns StaleShardVersion
• if the namespace is a view, the shard executes the request
  • the request will either return a view definition or CommandNotSupportedOnView
• if the namespace does not exist, the shard executes the request
  • the request will either return empty results or NamespaceNotFound