Thank you for your interest in BSS extension. The Magento Limit Order Quantity per Category is compatible with Magento 1 in details below: Community Edition: 1.9.x.x Enterprise Edition: 1.13.x.x - 1.14.x.x As you are using Magento 1.7 version, I regret that our extension won't work well. ​As Magento 1 will end of life soon, may I suggest you to consider about updating the system so you will get support from provider as well. If you have any further queries please feel free to contact me, I will be more than happy to help you.