The U.S. Department of Homeland Security has extended the REAL ID deadline, giving states two more years to meet federal requirements to make driver’s licenses with extra security features. Residents of noncompliant states will have until January 2018 before they must use passports or other official identification to board a domestic flight.

In a DHS press release issued Jan. 8, Homeland Security reported that 23 states are compliant with the REAL ID Act, and 27 states and territories have been granted extensions. Six states and territories—Illinois, Minnesota, Missouri, New Mexico, Washington and American Samoa—are noncompliant and do not have extensions.

The REAL ID Act was passed by the U.S. Congress following a post-9/11 evaluation of security measures. For a state-issued driver’s license or identification card to be REAL ID compliant, the state issuing it must take steps to increase security such as incorporating anti-counterfeit technology into the card; verifying the applicant’s identity; and conducting background checks on employees involved in issuing driver’s licenses.