Twilio has implemented mandatory two-factor authentication (2FA) as an additional layer of security for all paid customers starting October 12, 2020. This measure aims to protect customer accounts from identity theft and unauthorized access. To enable 2FA, users must provide a verification code sent via SMS or voice call, or use an authenticator app like Authy. The requirement excludes trial accounts and provides options for users to switch between 2FA methods at any time. Failure to comply may result in account suspension or closure. Twilio also plans to add additional options that do not rely on phone numbers for 2FA in the future, while maintaining data protection and security measures.