Software is required for sending and receiving bulk SMS, and various software packages are available. These software packages provide users with the opportunity to add as many phone numbers as required and these phone numbers can be managed in a variety of ways. Most SMS software applications allow the upload of lists of mobile phone numbers using a text file or CSV file. Some sophisticated systems can automatically remove any duplicated or improper numbers, and the mobile numbers may be validated before sending the messages. With enhanced software features, messages can be scheduled to be sent at specific times and/or days and bulk messages can be sent on national and international mobile networks as long as the bulk messaging software provider sends internationally.