Form 8453-C, U.S. Corporation Income Tax Declaration, is now historical. The 2021 revision is the last revision of the form. Prior version will be available on IRS.gov. Beginning with the 2022 tax year previous users of Form 8453-C will use new Form 8453-CORP, E-file Declaration for Corporations. Form 8453-CORP will be used for e-file declarations for Form 1120, 1120-F, and 1120-S filers.