San Francisco, Feb 18 : Micro-blogging platform Twitter has announced that it will no longer allow non-Twitter Blue users to use text messages as a two-factor authentication (2FA) method, after March 20. Also, users will now not be able to enroll in the text message/SMS method of 2FA unless they are Blue subscribers, the company said in a blogpost. After March 20, non-Blue accounts with text message 2FA still enabled "will have it disabled." Currently, the platform offers three methods of 2FA - text message, authentication app and security key. The company further mentioned that it "encourages" non-Blue users to "consider using an authentication app or security key method instead." "These methods require you to have physical possession of the authentication method and are a great way to ensure your account is secure," it added. Meanwhile, last week, Twitter had confirmed that it will charge Rs 650 per month for its Blue service with verification on the web and Rs 900 on Android and iOS mobile devices in India. In December last year, the micro-blogging platform relaunched its Blue subscription service with verification, costing $8 for Android users and $11 for iPhone owners per month globally. Moreover, Blue subscribers in the U.S. can create long tweets of up to 4,000 characters. Blue users will also see 50 per cent fewer ads in their home timeline. /IANS