Class method
System.String CMS.Ecommerce.Web.UI.CMSPaymentGatewayProvider.GetPaymentDataFormPath()
was removed. Use CMS.Core.Service<CMS.Ecommerce.Web.UI.IPaymentGatewayFormFactory>.Entry().GetPaymentGatewayForm(CMS.Ecommerce.Web.UI.CMSPaymentGatewayProvider, CMS.Ecommerce.Web.UI.IGatewayFormLoader) instead.