The Challenge Modes for the Scholomance and Gate of the Setting Sun dungeons are now available for testing, and should remain open for at least several days.
On the live servers, gear will only scale down, not up.
Challenge modes do not drop loot of any kind, though they do award Valor for completion. You will be able to reset the instance mid-run on the live servers. You can run them as many times per day as you like.
Will we get the 5 instances per hour lockout on Challenge modes?
This could be seen as extremely frustrating if we are trying to sort out a method for a beginning pull etc etc.
Resetting the instance while inside it, using the contextual menu option that is specific to challenge modes, does not count towards the lockout counter.