Sources from both NA and EU teams have confirmed that Overwatch Contenders' LAN playoffs will continue to be played on the "old patch", Version 1.14 to be precise, that went live on August 29th.
Week 6 of Contenders has continued with 1.14 over the last three days despite Blizzard pushing out 1.15 for public consumption earlier in the week. The decision will allow teams more time to adjust to the evolving meta that has seen increased Junkrat play, whilst further putting off the major Mercy rework and a nerf to D.Va's Defense Matrix that have headlined the current live 1.15 patch.
With a short turnover between the end of Contenders' regular season tonight and the LAN playoffs that are set to begin October 7th, switching to the new patch would be a major disruption for the competing teams who have been exclusively scrimming on the old patch up until now. Factor into that the travel and media commitments teams will face as they converge on the Blizzard Arena Los Angeles for Playoffs, and the available practice time is reduced to barely a week.
Patch 1.14 most notably buffed Junkrat's RIP-Tire and Concussion Mine, allowing him to hold two mines instead of just one. In addition, the patch had smaller buffs to the speed on Orisa's Fusion Driver bullets and Protective Barrier, Roadhog's Take A Breather self-healing ability and Widowmaker's Grappling Hook. These changes have prompted renewed interest in all three heroes from the pros, who have successfully brought them back into winning compositions.
Staying on this patch, instead of moving to Patch 1.15, also means teams will not be using will the new version of Mercy that features solo Resurrects as a 30-second cooldown ability and a new Valkyrie ultimate ability. In addition, D.Va's Defense Matrix will remain untouched for the remained of Contenders, and she will not have Micro Missiles that went live with the September 19th patch.