If someone files a return in tax season without renewing, what kind of correspondence will they receive?

A return filed with an expired ITIN will be processed.  However, certain tax credits and/or any claimed exemptions applicable to the expired ITIN will not be allowed. The taxpayer will receive a notice from the IRS explaining the change(s) made to their tax return and that you, your spouse, and/or your dependent(s) ITIN expired. Once the ITIN is renewed, any exemptions and/or credits previously disallowed will be reconsidered at that time. Until the ITIN is renewed, the taxpayer will be subject to interest and penalties for any tax owed as a result of disallowed exemptions and credits.