One month ago, the patch notes from beta promised it would be:
Level 60 Onyxia should be available once again.
This still hasn’t been fixed. Trying to enter the instance gives an error message “Transfer aborted: instance not found”.
To all the people saying it’s because Ony was reintroduced as a level 80 raid, in vanilla wrath, the level 60 version was accessible before she was upgraded. If we’re getting staggered content, it’s only fair we still get access to the level 60 version. (Plus, like I said above, the developers probably knew that, which is why they mention the level 60 version in the patch notes from last month.)
Please fix this. There’s only so much time for people to have fun with the level 60 version before it disappears forever.