The EVE Online developer blog has been updated with a comprehensive article detailing the history of the Serenity server. The ostensible goal of the post is to correct "incomplete and sometimes misleading" information about the server that largely caters to the Chinese EVE community.
The situation with Serenity is quite different than with Tranquility in that Tranquility is completely operated internally by CCP, while Serenity is operated by TianCity. The servers are in their infrastructure and they perform all maintenance and updates to the Serenity cluster. Initially, CCP helped TianCity set up the servers and get EVE running on them, as well as their websites, integrating their billing system with EVE and fine-tuning for their environment. Over the last several months of the beta test, TianCity have gradually taken on more and more of the daily operations and now run the Serenity cluster with little assistance from CCP. CCP develop new feature expansions for EVE and they are translated and adapted in minor ways for China, at which point TianCity deploys them to the Serenity server, according to a schedule best suited for the Chinese market.
Read the full post on the EVE Online site.