The open beta for Battlefield 1 goes live on August 31st (this Wednesday) on all formats. With its strong market position the PlayStation 4 version is perhaps the most important one, and normally you have to be a Playstation Plus subscriber to enjoy online play on PS4.
This will however not be the case for the Battlefield 1 beta. Through the game's official Twitter account developer DICE has confirmed that anyone will be able to join in, regardless of their PS Plus standings.
"You do not need a PS Plus account to play the Battlefield 1 Open Beta on PlayStation 4"</i>, writes whoever is in charge of the official Battlefield feed.
In contrast people who play on Xbox One will require an active Xbox Live Gold membership to partake, as confirmed in the comments of the same Twitter post. Of course, if online multiplayer is your thing, you probably have an active account on your console either way.