Yes, you can upgrade your license. To upgrade a license, log into your account page on highfiveplugins.com, locate the purchase record for the plugin you wish to upgrade and click on View Licenses on the right side of the screen.
If your license key has upgrades available for it, a View Upgrades link will be displayed on the right side. Click this link to see the available upgrade options.
The total cost of the license (without VAT if you’re in the EU) upgrade will be displayed next to each upgrade option. Click on Upgrade License to proceed to the checkout screen where you can complete the purchase.
Once you have completed the upgrade purchase, your license will be upgraded and you can now activate it on additional URLs.