It was mentioned back when they implemented the 11 buff, so I'd guess it would be coming in the September version update maybe? They have not specified a date on that yet, nor any potential requirements for using it. As far as I know, it's still on the table. If someone can confirm that it's not available in the Test Server, then it's likely being pushed to whenever they implement Cait Sith/Atomos and the other post-update job adjustments.