We know the Battlefield 1 Open Beta begins on Wednesday, August 31, but DICE isn’t saying when it’ll end. “The Open Beta begins August 31st, but we don’t have the end date just yet,” they wrote on Twitter. “Stay tuned for more Beta info soon.” According to Czech gaming site Zing though, a press release from EA says that it runs until Wednesday, September 7.
Although the Battlefield Twitter account said last month that Battlefield Insiders would get one day early access to the open beta, they’re now saying, “We have not confirmed the beta starts 1 day early for Insiders. You’ll have to wait until it’s announced.” They also don’t know when the codes for Insiders will be sent out, but it’ll be closer to the beta start date. As for how big the Open Beta client will be, fan site Battlefield Bulletin is reporting that an Xbox One product page showed a download size of 6.2GB. However, this could change for PlayStation 4 and PC, and DICE may add further updates ahead of August 31 that increase the size.
The Open Beta includes the Sinai Desert map and these two modes:

Take Control in Conquest Mode
An all-time fan favorite of Battlefield players, Conquest is a large-scale game mode with up to 64 players fighting for the control of key objectives. With large armies on foot or behind the wheel and the addition of fearsome Behemoths, Conquest brings together all the elements of the signature Battlefiel...