Upgrade Store
From Shopnix Help
What is Upgrade store?
Where I will get Upgrade store feature?
In order to receive the uninterrupted service you have to renew your subscription.
When you enter to the store admin ,at the top you will find a red color message line like below
just click on that message and you are redirect to a new page like below
Carefully read all the information then choose your plan click on the
you will redirect to the payment page like this