Ran a proof-of-concept IPv6 implementation on a staging environment, to confirm support for logging, monitoring, IP-based access controls, and other internal mechanisms. Later, exported the implementation to production. Briefed support teams, published AAAA records, and wrote public communications (as linked).
Use of IPv6 on Bitbucket was slim, due (perhaps) to sluggish adoption of that protocol version in corporate environments, but Bitbucket was the first major repository host to support IPv6 connectivity in July 2016.
Project link: https://bitbucket.org/blog/bitbucket-cloud-now-available-ipv6