https://www.pcgamer.com/the-battlefield-1-premium-pass-will-be-free-for-a-week-after-the-battlefield-5-beta/

The Battlefield 5 open beta begins on September 6, or September 4 for Origin Access subscribers and people who have committed themselves to the cause by way of a preorder. It runs until September 11, and when it's over, Battlefield 1 owners will be able to grab the full BF1 Premium Pass for free. 

The Premium Pass covers all maps, weapons, vehicles, modes, and classes from the They Shall Not Pass, In the Name of the Tsar, Turning Tides, and Apocalypse expansions. If you've got Battlefield 1 but took a pass on the Pass, it's a lot of extra stuff to shoot at, with, and from.