Yes. Sigma’s website maintenance offerings are a pay-as-you-go service and you can upgrade or downgrade at any point of time. As your business grows, you may want to take advantage of the advanced features, and Sigma makes it easy for you to proactively upgrade your store. The changed website maintenance plan will be effective from the next billing cycle.
If you are interested in the upgrade or downgrade of your website maintenance plan, reach out to our Magento maintenance support team at firstname.lastname@example.org