The developer of an FTP server utility can create the service in any way, but the software will only be able to work universally interacting with other devices that don’t need to have the same software installed on it, if the developer follows the common FTP standards. All FTP utilities will include all of the commands stipulated in the relevant RFCs and then will possibly also have extra functionality. CHMOD is not specified in the FTP standards and therefore, it is an optional extra that some developers program into their software. It doesn’t have to be included in every implementation.