Leaked internal T-Mobile memo reveals the end of a feature used by 1.5 million subscribers

A leaked internal memo from T-Mobile, discovered by The T-Mo Report, reveals that the nation's second-largest carrier is planning on ending support for its "Block All/Blacklist All Short Codes" account setting starting this coming Wednesday, August 18th. As many as 1.5 million existing T-Mobile customers using the feature will have it removed between August 31st and September 2nd.

A short code is a telephone number made up of four, five, or six digits. Businesses use short codes to send high-volume messages via MMS or SMS to customers including alerts, codes for two-factor authentication, and marketing messages. Allowing its customers to block or blacklist all short codes led T-Mobile subscribers who enabled the feature to complain to the carrier that they weren't receiving two-factor authentication codes, important messages from their financial institutions, and more.

The resulting flood of calls made by T-Mobile customers who blocked or blacklisted short codes became a headache for T-Mobile's customer service department. T-Mobile will still allow customers to block individual short code numbers following the removal of the option to block all short codes.

Starting this coming Tuesday, August 17th running through Thursday, August 19th, T-Mobile will send out text messages alerting its customers to the change. If you're a T-Mobile customer and never blocked short codes from appearing on your mobile device, you won't notice any change.