Blizzard put up a new blog post today and announced that if you still want to get the rewards from challenge modes now is the time to do so! Sadly no time frame was given. Check the full announcement below:
Challenge Modes are designed to offer as close to a “normalized” difficulty as possible, and they’re tuned to be tough to master. With Warlords of Draenor’s class changes, itemization changes (e.g. the removal of Hit and Expertise), and—of course—increased level cap on the horizon, the difficulty of Mists of Pandaria’s dungeons will no longer be tuned the same as they were. In the spirit of fair play, when the aforementioned patch is released a little while before the new expansion launches, the current slate of Challenge Mode dungeons will no longer be available, and the achievements they award will be converted to Feats of Strength. The reward items will still be available for purchase by those who qualified prior to the end of the season, but it will not be possible for new players to earn those rewards going forward.
If you still need to earn your Undaunted title, Ancestral Phoenix, or class-specific Transmogrification sets, now’s the time to get out there and prove your worth. In Warlords of Draenor, an entirely new set of Challenge Modes will be available . . . and with them an array of new rewards for you to earn. Until then, stay sharp!