Twitter stated last month that its two-factor authentication (2FA) solution will be available only to Twitter Blue users.

Twitter has now proclaimed that unless an account is a Twitter Blue subscriber, it will no longer be possible to enroll in the SMS mode of 2FA. The new rule goes into force today, March 20.

2FA is a security tool that aids in the protection of your Twitter account from hackers.

To enter their accounts, users must input a password as well as a code or security key. It is now available to Twitter Blue users.

Twitter Blue costs $84 per year ($8 per month) for web users. Android and iOS users, on the other hand, must pay $11 for the service.