Quote Originally Posted by Blueyes View Post
From http://blog.us.playstation.com/2015/...d-new-details/ on Mar 07, 2015.
If you already own A Realm Reborn and you get Heavensward, you’ll be able to at least enter Ishgard. The new jobs added in Heavensward are not tied to the main story, so those are accessible as well.
Regardless of if you completed 2.55 or not, you can still get into Ishgard and get access to the jobs. You just can't go too far past that. So the surrounding areas and the Heavensward story will be gated behind the 2.55 completion since they tie into the story. But if you completed up to 2.3 lets say...and then you buy Heavensward. You can go into the new city, get your shiny new jobs, then continue on with the story from where you left off with the new jobs (assuming it's been leveled.)