Further, non-compliance of UDIN directive may attract Disciplinary Proceedings as per Clause 1 of Part II of Second Schedule of The Chartered Accountants Act, 1949. This UDIN System has been developed by ICAI to facilitate its members for verification and certification of the documents and for securing documents and authenticity thereof by Regulators. Accordingly, the Council at its 374th meeting decided to implement UDIN , therefore it has been made recommendatory with effect from 01st July, 2018, and later on it would be made mandatory. UDIN is a 18-digit number for certificates/reports/documents attested by full-time CAs. Learn how to register, generate and verify UDIN on UDIN portal, and why it is mandatory for CAs.