In a recent official tweet by @Battlefield, they have confirmed that Battlefield 4 will again be put on display for the masses however this time a playable beta will be shown at the Microsoft Xbox One booth.
Created in 2004, the Penny Arcade eXpo (PAX) is a series of gaming festivals held in Seattle, Boston, and Melbourne, Australia. PAX was created by Jerry Holkins and Mike Krahulik, the authors of the Penny Arcade webcomic, because they wanted to attend a show that gave equal attention to console gamers, computer gamers, and tabletop gamers
PAX Dev will be taking place in downtown Seattle two days before PAX Prime (August 28th and 29th) at the Washington State Convention Center. With no press access, PAX Dev is a place to share, debate and learn in which developers can speak freely and focus entirely on their trade in a safe and comfortable environment.
More info at PAX’s site.