REVENUE MEMORANDUM CIRCULAR NO. 4-2009 issued on January 26, 2009 extends the deadline for the submission of the Annual Information Return of Income Taxes Withheld on Compensation and F inal Withholding Taxes (BIR Form No. 1604- CF) until February 27, 2009 due to technical and systems problems being encountered in the enhancements of the Data Entry Module for the preparation of Alphalists of Employees and the Validation Module to check technical specifications of those using their own extraction programs/excel format/data entry module.