Ebay introduce new changes connected to Business Policies. As result, a seller can start to receive warning or error related to this change.  

This is related to new ebay requirements https://go.developer.ebay.com/coming-soon-business-policies-opt-inopt-out-will-be-enforced

So for a seller that just get the warning. Ignore it. For a seller that receive an error and can't list a new item, please sing out from business policy feature.

More information regarding business policy you can find there (including how to include/exclude it for seller account).http://pages.ebay.com/help/sell/business-policies.html

You can opt out of business policies by clicking the opt out link in the upper right corner of the Manage your business policies page in My eBay > Account > Manage your business polices. If you opt out, the payment, shipping, and return details in your current and scheduled listings aren't affected.

PrestaBay 1.7.x, 1.8.x, 2.6.x, 2.7.x include all support for ebay Business Policies.