My employer sent me a second W2 and wrote "revised" on the envelope. The W2 form is not a "Corrected" W2 form. Do I only enter the most recent one?

No, you should verify with your employer if the second W-2 is a "corrected" W-2 and if the corrected W-2 was sent to the IRS.

If your employer did not send the "revised" W-2 to the IRS and you enter the "revised" W-2 it will not match the IRS records and could cause your return to be rejected.

If the "revised" W-2 was sent to the IRS then enter it in your tax return and.