Can't find how to enable IK on another user's rigged model, what's the catch? I'm trying to help a user in this question , but he's using a complex posed human-body, and rigify. He posted the model here: http://pasteall.org/blend/index.php?id=43931

I would like to check how to solve his problems, but I need to change the model pose, it seems locked, there should be a sort of IK switch for the rig but I can't find where it is. I'm quite a rigging noob, sadly.

He told me hs's using rigify, but even after enabling it, I can't still pose this model... I'm using Blender 2.78, but could try older versions too.
Bones that are visible by default in this file have all transforms locked.You have to make visible armature layers, that contains controlling bones. Here is the image, that shows this.