HMRC has updated its guidance What happens if you don't report payroll information on time to show that the Full Payment Submission (FPS) three day easement has been extended to 5 April 2018.
However, HMRC won’t charge a penalty if:
the FPS is late but all reported payments on the FPS are within three days of employees’ payday (this applies from 6 March 2015 to 5 April 2018). However, employers that persistently file after the payment date but within three days may be contacted or considered for a penalty they’re a new employer and the first FPS was sent within 30 days of paying an employee it’s the first failure in the tax year to send a report on time (this doesn’t apply to employers that register with HMRC as an annual scheme).