The HMRC deadline for 2013/14 FPS submissions has now lapsed (19th April). Therefore, if you attempt to submit an FPS for a 2013/14 pay period HMRC will reject it.
Any 2013/14 payroll submissions, including additional payments, corrections or omissions, must now be submitted to HMRC using the Earlier Year Update (EYU) submission.
HMRC published a new 2013/14 End of Year guide today, http://www.hmrc.gov.uk/payerti/end-of-year/finish-payroll.pdf
A BrightPay 2013/14 end of year checklist is also available, simply click here https://www.brightpay.co.uk/5_Steps_to_EOY.pdf.