There are a few changes going into effect. The biggest is that if you issue a refund to a buyer, PayPal is not going to return your transaction fees. Some sellers have already updated their policies so that the buyer pays those fees.
https://www.paypal.com/us/webapps/mp...-policies-full
We’re changing how we treat refunds. If you refund (partially or fully) a transaction to a buyer or a donation to a donor, there are no fees to make the refund, but the fees you originally paid as the seller will not be returned to you.