If you’ve chosen to use certification, it’s possible that the certification period may include one or both of the increases in the minimum contribution levels. Your payroll will need to be ready to calculate and deduct the increased amounts.
The Department for Work and Pensions has produced guidance for employers on the process of certification, including a template of the certificate. This template includes that the employer certifies at the current minimum up to 5 April 2018 and then at the increased minimum from 6 April 2019.
Or you could choose to certify at the higher increased amount for the whole certification period. This means you won’t need to make changes to payroll on 6 April 2018 and on 6 April 2019, as the contributions will already be being calculated and deducted at the increased minimum contribution rate.
If you haven’t done either of these, then you’ll need to end the certification period early and re-certify the scheme from 6 April 2018.