When I first heard of the change, I also heard that Serenity had not received any updates in nearly two years. A quick look on Eve-Offline showed Serenity was still running version 14.08, which I believe was the version before the introduction of Alpha clones and a new business model. In a dev blog published today, CCP referenced the change.
"EVE Online: Ascension, which first launched on Tranquility in November 2016, saw the introduction of the most significant changes in the history of EVE Online. It certainly changed the wat [sic] that our pilots play EVE and we’ve been thrilled with the effect it’s had on the landscape of New Eden.
"Nevertheless, we understand that the Chinese market may be quite different, so we will not hastily launch it on Serenity until we find the correct way in which to do so.
"Meanwhile, on the corporate level, by seeing the significant potential for positive change that this expansion may have on Serenity and its community, we have been investigating how best to update or business roadmap for the Chinese market.
"After evaluating options, and speaking with potential Chinese business partners, we finally made the difficult decision to move on. After supportive and considerate negotiations with Tiancity, we both agreed to draw our partnership to a close, but to keep Serenity running as normal until we are ready to take EVE in China to the next level."
The history of EVE Online in the PRC is a little rocky. In 2006, CCP contracted with Optic Communications to operate EVE in China. In July 2007, Optic was acquired by CDC Games, a "pioneer of the 'free-to-play, pay for merchandise' model for online games in China." CDC Games continued running EVE until the end of 2011. A dev blog in December 2012 described the end of CCP's relationship with CDC.
"In 2011, our licensing agreement with CDC, which had at that time acquired Optic Communications, was going to expire in July. After careful evaluation, the overall business performance of our partnership and EVE Online in China, we decided that shifting to a new partner would be the right move for EVE. Even though in the end we made the hard decision to not extend the license with CDC, we were really thankful for their hard work to launch EVE Online in China, and their contribution to its growth during its inception years. The operation team worked to the last moment on the day of April 1st, 2012, when we temporarily closed the server cluster for the transition."
In truth, CCP's search for a new operator was forced by CDC Corporation, the parent company of CDC Games, filing for bankruptcy protection in October 2011. The company went out of business on 19 December 2012.