Upgrading is moving up tiers within the same product. You can move between tiers at any time.
EXAMPLE:
You can move from Sage Sole Trader Free to Paid, but you can't upgrade from Sage Sole Trader to Sage Accounting. They aren't the same product, so you need to add a new business to move to Sage Accounting.
Cause
Resolution
From your business name dropdown menu, select Manage business, then View subscriptions.
Select Manage subscriptions from the Subscription information section.
Choose Select subscription to upgrade to a higher tier or add a new product to your existing subscription.
TIP:
Select Compare features to view the differences between subscription tiers.
Review the Pricing plan section to make sure you're happy with the changes.
Select Apply selections.
Finally, confirm your billing address and payment method.