SAP SE Google University of New Hampshire Interoperability Labs University of New Hampshire Interoperability Labs This document provides guidance for application developers and software as a service providers on how to approach IPv6 testing in Dual-stack (IPv4+IPv6), and IPv6-only scenarios, including "IPv6- only-strict" scenarios without any connectivity towards any relevant IPv4 endpoint. It discusses common misconceptions about the degree to which operating systems and libraries can abstract IPv6 issues away and explains common regressions to avoid when deploying IPv6 support.