Holdout is a game mode first introduced in Update 1.6. The only map currently available is Jericho.
In Jericho, squads of up to five players are charged with defending a Melding Repulsor from waves of Chosen until the Repulsor is destroyed, everyone in the squad becomes incapacitated, or if the squad chooses to leave at the end of a round. Each round gets progressively more difficult and squads are challenged to holdout for as many rounds as possible, there is no limit.
Each round of Holdout consists of five waves of enemies that will attack from different directions and attempt to destroy the Repulsor and its defenders. As teams progress through rounds, more challenging combinations of enemies will join the fray, such as an all sniper wave, an engineer wave, a mix of Chosen Obliterators, Chosen Mortarmen, Siegebreakers, or even Chosen Juggernauts! If an ally is downed during the round they can be revived (no self-revive tokens allowed). Should the remaining members of the squad complete the full round; their downed allies will be automatically revived to prepare for the next battle. Beware, though, if all members of the squad are incapacitated, or the Repulsor is destroyed, the mission will end as a defeat.
At the end of each round, a dropship arrives and offers the squad the opportunity to leave with what they’ve earned so far. The choice is now to leave Jericho or risk surviving a tougher round for more rewards. Squads that fail to survive a round will only earn half of the rewards earned when defeated, so be sure to choose your battles wisely! Holdout rewards will include crystite, experience, and modules.