: Previously used for certain tax payments, these are no longer supported for paper processing as of recent tax years.
: The Corporation Tax Modernized E-File Handbook , which details the technical requirements for filing and recent changes for the 2025 tax year. nys-dtf-ct
The most "interesting" aspect for filers currently is the . Primary Corporation Tax Forms : Previously used for certain tax payments, these
: Most corporation tax extensions and estimated tax payments must be filed electronically . Paper versions of these extensions (except Form CT-5.1) are generally no longer accepted for processing. nys-dtf-ct
: Provides specific procedures for e-filers and software developers participating in the NYSDTF program. Important Filing Note