Vonage is deprecating its US Shared Short Code API due to T-Mobile and AT&T's new code of conduct prohibiting shared originators of A2P traffic. This change affects customers using the US Shared Short Code API for SMS communications, including Two-Factor Authentication. To migrate, users must switch to one of the available alternative APIs, such as the SMS API or Verify API, which offer more flexibility and features. The SMS API requires adjustments to code and configurations for sending and receiving SMS messages, while the Verify API provides a new method for managing verification requests and codes. Users can purchase new numbers from the Developer Dashboard to send and receive SMS messages and register custom templates within their project. For further information on using these APIs, users should refer to the Developer Dashboard and Pricing pages.