IPv6 is not a &quot;wildly different network stack&quot;. It retains almost everything of the IPv4 stack. It replaces some small parts of the stack (e.g., DHCP by stateless auto-configuration, which doesn&#x27;t affect applications). Updating an application-layer IPv4 program to support IPv6 <i>is</i> usually just a matter of fixing the structs&#x2F;API calls.<p>And how is it &quot;much more complicated&quot;? IPv4 with layers of NAT bolted on top of it in an ad-hoc fashion doesn&#x27;t strike me as a paragon of simplicity. The IPv6 world seems much cleaner to me.<p>Also, IPv4 addresses absolutely are complicated enough to have warranted their own Wikipedia articles: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Classful_network" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Classful_network</a>, <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Classless_Inter-Domain_Routing" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Classless_Inter-Domain_Routing</a>. But it doesn&#x27;t matter - for the most part, applications don&#x27;t need to care about the structure of an IPv6 address.