Update 12/7: BioWare has given an update to when the demo for Anthem will be released, giving more specific time frames for when fans can expect to play it.
Announced on EA’s website, there will be two release dates for the demo: one for “VIP” players, and an open demo soon after. The VIP demo will run from January 25–27 and be available to those who pre-order Anthem or are an EA Access or Origin Access subscriber at the time of the demo. Those who participate will also get an exclusive VIP demo item.
The open demo will run from February 1-3 on PS4, Xbox One and PC and will be open to all players.
Source: IGN.com BioWare Further Details Anthem Demo Release Dates