DRIVERS-194. Drivers that provide a createCollection or similar helper must support the new createCollection command options added in MongoDB 2.8. Drivers that already accept arbitrary options for these helpers only have to review and adjust documentation. Drivers that have builders or validate all options will have to add explicit support.
SERVER-16137 for more information.
Since the server does not report an error on an invalid field in the createCollection command, if you want to validate you have to use the listCollections command, e.g.