Employers: Withholding guidance coming soon. With the new tax law now in place, Form W-4 will need to be substantially revised. On Dec. 26, the IRS announced it is working on withholding guidance and anticipates issuing it this month. Employers and payroll companies will be encouraged to implement the changes in Feb. The IRS stated the information will be designed to work with W-4 forms already filed. Use of the new withholding tables will allow employees to see changes in their paychecks as early as Feb. Until then, employers should continue using 2017 tables.