Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I just got this morning. and then after minutes. it turned back to yellow thumb up. Maybe it is a server side
 
Is that really what that option does? I recall it being there even before quick reply was introduced and mainly relating to being able to reply with a (usually predefined) message to an incoming call.

I think it does really turn quick reply feature on/off on lock screen. See also the iMore article.
I do hate it that i can't use a third party swipe keyboard (e.g. Swype) on my lock screen for quick reply. Grr.
Apple should really come up with their own swipe keyboard.
 
Today quick reply finaly work for me out of nowhere without updating the app or anything. About time.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.