Perhaps 15.0 has a more GPU-dependent computation bias that makes it ultimately stronger if given a GPU. And all those incremental improvements add up, if for example compared to something like 13.3, which I would consider to have been a benchmark for a comparatively long time.

Zen lost today shows that it's still unreliable even with Chinese rule.
Though FineArt which is stronger than Zen is still not on the 'unbeatable' level.
Update: lost today due to horizontal line effect (basically a popular excuse for strong programs now)

https://twitter.com/webigojp/status/877453072129064961

Mlily Cup 2nd Round DeepZenGo lost with Wang Haoyang 6p (of 0.5 point):

Update on DeepZenGo

“DeepZenGo has improved by one stone compared with where it was in March, and our goal this time is to get to the top spot,” said Hataki Kato, the AI’s creator. “Our team wants to make the best Go software to help people.”

LOL at 'Hataki Kato', anyway this is interview just after Zen won in first game and before its lost on second game, so Hideki is being overly confident.

https://www.yicaiglobal.com/news/japane ... tournament

This interview is after it lost on second game

"Everything looked fine at the beginning of the contest until the machine made mistakes in the middle of the game.

DeepZenGo's performance "did not meet my expectations," said Kato, who believes a program bug was caused by technical problems, adding that a misjudgment made the machine confused whether to win or lose.

World top-ranked player Ke Jie sent his congratulations to Wang after the game. The 19-year-old talent insisted on figuring out the weaknesses of DeepMind's Go-playing program AlphaGo and has tried to defeat the machine after he lost a battle in Wuzhen last month.

Wang said he had been defeated by DeepZenGo on Internet games before. But these games were fast, and the contest was slow. Human players normally do better in slow games."

from http://www.ecns.cn/cns-wire/2017/06-22/262555.shtml

and

After the victory, Ke Jie, a Chinese player who is the world’s number one and was whitewashed three to nothing by Google DeepMind’s AlphaGo last month, congratulated Wang, describing him as “the hope of humanity.”

DeepZenGo didn’t play as well as it should have, Hataki Kato, its developer, said after the game, blaming a technical problem within the program. It mistook a dead group on the left side of the board as an alive one, Kato added, saying that such a misjudgment is obviously a major bug in the program.

from https://www.yicaiglobal.com/news/chines ... tournament