Patch 6.86f has been released just days before the start of the group stage of the Shanghai Winter Major, and is exclusively nerfs to invoker.
Pros and scrubs alike have been complaining about Invoker featuring (and dominating) every game. Icefrog has agreed, and has nerfed deafening blast, one of the most recent changes that have boosted him to the top pickrate for the patch.
Deafening blast’s knockback is no longer a hard disable and the disarm debuff now starts at the start of the knockback, essentially shortening the time Invoker can disable enemies.
Full details can be found here.