Employers in the United States, before engaging a new employee in permanent work, is required to verify the employee's identity and right to work in the United States by completing the Employee Eligibility Verification Form, Form I-9. Some documentation accepted by the form, such as U.S. Passport Cards and U.S. Passports, can be used by an employee to demonstrate both the right to work in the United States and the employee's identity. Other pieces of documentation accepted by the Form may be used to verify identity, such as a State-issued ID card or driver's license, but must also be supplemented by documentation demonstrating the employee's immigration status, such as a Social Security Card or Birth Certificate. The current revision of the form accepted as valid is dated February 2, 2009; no other versions of this Form may be used. The new Form includes a substantial change in the acceptability of expired documents. While previously employees were able to use expired documents, such as a U.S. Passport, to verify identity and work authorization, the new rules prohibit employers from accepting expired documents for the purposes of Form I-9 employment eligibility verification.