(UPDATE 1) In this blog from Vince Zampella, CEO Respawn Entertainment, some more info was revealed, including that the DLC will also be free on Origin to celebrate the one year anniversary of Titanfall.
(UPDATE 2 ) This post from the Official Titanfall Twitter sheds some light how long this promotion will last.
@deathspankd This content is free starting now and will remain free for all users who purchase Titanfall for Xbox One, Xbox 360 and PC— Titanfall (@Titanfallgame) March 11, 2015
Original article below.
The three add-ons are Expedition, Frontier's Edge, and IMC Rising. There is no word on how long this promotion will last and it is unclear if this the Origin version of Titanfall on PC will also receive such a deal.
DEAL: All Titanfall DLCs are available for FREE on both Xbox One and Xbox 360! Visit the Xbox Live Marketplace to see the deal!— Apex Legends News (@TitanfallBlog) March 11, 2015
Neither EA nor Microsoft have said anything about this deal which leaves other details unknown.
It was March 11 2014 when Respawn's first game was released on PC and Xbox One. With the Xbox 360 version being delayed a month eventually coming out April 8 2014. Titanfall was the fastest selling new IP on the Xbox One and was a big exclusive for Microsoft as it did not appear on any other competitors consoles.
Even though officially unannounced, EA's CFO Blake Jorgensen has spoke of a sequel to Titanfall and the possibility of it being on other platforms. "Last year it was on the Xbox only; in the future, we haven't yet announced, but we'll probably have another Titanfall game. It will probably be a bigger footprint than just a single platform."