The continent Draenor is identical to what became Outland at some point or in another time line. Many third-party magazines have stated this, and it is fairly obvious looking at the names of various zones and places.
However, has this connection (edit: the fact that this must be the past of Outland, or an alternate timeline) ever been referenced on screen (edit: in Warlords of Draenor)? For example, a non-player character saying something like "Looks like something has changed the time line" or "This must be how Outland has looked like in the past".
I have levelled up to 100, completed the garrison campaign up to the point of reaching Tanaan Jungle, and I can't remember anything like this. A friend says he's sure to have seen it, but can't remember details. Can you?
Update
Before WoD, it was of course known that the name of the planet that became Outland was "Draenor". One could assume that the player makes the connection based on this, but I would have expected Blizzard to let at least one NPC (or readable in-world item) inside Warlords of Draenor content actually state the connection and timeline difference.
Best Answer
(Emphasis added.)
The most direct acknowledgments are from the quest Fugitive Dragon:
and from Temporal Juxtaposition:
Two quests reference Outland specifically: Settling Grievances
and Completionism
but neither of them specifically mention the timeline shifting.