More than a year after hackers managed to manipulate the system in order to steal information on more than 720,000 U.S. taxpayers. The IRS suspended the service last May after it was discovered attackers had been accessing sensitive information via the platform. The revenue service maintains that the service has been retooled and bolstered by what its calling an enhanced authentication process. To use the service going forward users will be required to have a Social Security number, an email address, a mobile phone with their name on the account, and specific financial account information.
Source: https://threatpost.com/one-year-after-hack-irs-debuts-updated-get-transcript-service/118608/