mongodb setFeatureCompatibilityVersion command not found
The documentation for setFeatureCompatibilityVersion shows it being new as of MongoDB 3.4, so it can't be run on a 3.2 server process:
https://docs.mongodb.com/v3.4/reference/command/setFeatureCompatibilityVersion/

The upgrade steps describe that running this command should be done after the server processes have been upgraded to 3.4.