According to caster Jason Kaplan, APAC Premier 2017 will be played on 1.16, the most recent patch to hit the game, as opposed to an older version of the game. Recently, tournaments played on the tournament realm have played on older patches so teams could play matches on game versions they have ample time to practice in.
Just got the info that APAC Premier 2017 will be played on the patch that went live today! So Mercy has 2 res charges with ult used— Jason Kaplan (@JKaplan) October 18, 2017
Many were under the assumption that APAC, and even the World Cup playoffs, would be played on patch 1.15, which most notably changed D.Va and Mercy. Even after the game updated to 1.16 on Tuesday, it seemed unlikely that APAC would be playing on the live version of the game given the recent pattern of tournaments running on older patches. However with Jason Kaplan's announcement, it can be assumed both APAC and the World Cup will be running on patch 1.16.
There ares some concerns regarding why Blizzard would want to stray from the norm and have teams play on a patch with such little time to practice. The general consensus of Mercy in 1.15 was that she was overpowered, and while she was played in tournaments without access to the tournament realm, there was still some anxiety over how she would affect play in a major tournament. Additionally, 1.16 fixes Lucio's wallriding speed after a recent bug fix ended up nerfing it, as the current version of Lucio gives no advantage to players who bind jump to scroll wheel. Previously, Blizzard banned the use of scroll wheel jump in Contenders playoffs after deeming it an exploit to gain more speed on the character.