After upgrading to mongo-1.6.1, I'm getting messages dumped to my terminal when my Rails app starts up (running "rails console" for example).

$ rails console
host is not a valid option for Mongo::Connection
port is not a valid option for Mongo::Connection
Loading development environment (Rails 3.2.2)
irb(main):001:0>

This seems to be coming from new code in mongodb/mongo-ruby-driver@8e64c74d that validates the options being passed in. I believe that this is because the host and port options need to be filtered out by Mongoid when it establishes the database connection, because these options should have already been used when generating the connection URI.