"The revision date of the new Form I-9 is printed on the lower left corner of the form. Employers should not complete a new Form I-9 for existing employees, however, if a properly completed Form I-9 is already on file."
USCIS – Employers Must Use Revised Form I-9, Employment Eligibility Verification
Employers Must Use Revised Form I-9, Employment Eligibility Verification. Released May 7, 2013. USCIS will no longer accept previous versions of Form I-9. WASHINGTON—U.S. Citizenship and Immigration S…