@lanodan @alcinnz Then they can have No-IPv4 Wednesdays, or something. But I think going the whole way might be wise.
Microsoft has substantial IPv6 infrastructure; I bet they could make the transition between the announcement and the implementation of no-IPv6. And if they don't… we don't *need* GitHub. There are plenty of mirrors to get software that's hosted there (not to mention IPv4–IPv6 bridging proxies), and there are plenty of alternatives to host your own software on.