The Internal Revenue Service said Tuesday that taxpayers are receiving letters with the wrong date listed for their Identity Protection Personal Identification Numbers, which are generally issued to victims of tax-related identity theft.

“Due to an error, taxpayers are receiving Identity Protection PIN letters with an incorrect year listed,” the IRS said in a statement. “Taxpayers and tax professionals should be advised the IP PIN listed on the CP 01A Notice dated January 4, 2016 is valid for use on all individual tax returns filed in 2016. The notice incorrectly indicates the IP PIN issued is to be used for filing the 2014 tax return when the number is actually to be used for the 2015 tax return. The IRS emphasizes the IP PIN listed on the CP 01A notice is valid for the 2015 returns. Taxpayers and their tax professionals should use this PIN number for 2015 tax returns, which the IRS will begin accepting from taxpayers starting Jan. 19, 2016. The IRS apologizes for the confusion and any inconvenience.”

The CP 01A notices are all dated Jan. 4, 2016, according to the IRS, but were mailed in late December. Taxpayers are receiving the letters now through mid-January.

An IP PIN helps the IRS verify a taxpayer’s identity and accept their electronic or paper tax return. The IP PIN prevents someone else from filing a tax return with a taxpayer’s SSN.

If a return is electronically filed with the taxpayer’s Social Security Number and an incorrect or missing IP PIN, the IRS’s systems will reject it until it is submitted with the correct IP PIN or if the taxpayer files on paper. If the same conditions occur on a paper filed return, the IRS will delay its processing and any refund that may be due to safeguard the taxpayer.

The IRS said the issue did not affect anything else involving the IP PIN process.

An IRS spokesperson emphasized that the IP PIN is good, and the date at the top of the letter was good.  "All the letters are out," she said. "It’s just the wrong tax year listed."