Under auto enrolment legislation, minimum pension contributions are required to increase over time.  The next increase is due to take place from April 2019, as follows:

Employer Contributions 3%

Employee Contributions 5% (includes 1% tax relief)

You are able to find out more information about this and your general ongoing duties in the link below:

https://www.thepensionsregulator.gov.uk/en/employers/new-employers/im-an-employer-who-has-to-provide-a-pension/declare-your-compliance/ongoing-duties-for-employers-