Kentucky enacted a new 5% flat tax rate in May 2018. This new rate is effective for tax year beginning January 1, 2018. ezPaycheck 2018 payroll software clients and ezAccounting 2018 software clients can follow the guides below to update.
Source:
https://revenue.ky.gov/Forms/42A003(TCF)%202018%20Withholding%20Tax%20Formula%20(Released%20May%202018).pdf