What version of CPTL should I use?

The current version of CPTL is v2016A.1. This version of CPTL is based on Canada Revenue Agency publication T4127 (E) Rev. 15 - Payroll Deductions Formulas for Computer Programs 100th Edition Effective for payrolls beginning January 1, 2016. CRA usually publishes updates for payroll deduction formulas twice a year, effective January 1 and July 1, and CPTL is updated accordingly. New versions of CPTL are usually made available for download by authorized licensees within seven days of CRA's publication of an updated T4127.