Things that have been moved around or changed. getFieldDottedOrArray -> ElementPath.getFieldDottedOrArray (was unattached function, now static function on ElementPath class) isAllDigits -> ElementPath.isAllDigits ( now static function ) Status objects are now generic objects having a 'code' property that is a string of the error code that mongo uses (e.g. {code:'OK'}). StatusWith is now rolled into status as a result field. status.getValue() is now status.result debugString takes one argument 'level', as does debugAddSpace. Debug statements are printed to console.debug() verify is a macro function that throws an exception if the input is falsey, with the current file and lineno, so there is no need for the function itself