In answering questions about rewards gained from the beta, the Twitter account mentioned not only the open beta but also that rewards can be gained by participating in either the closed or open betas. The open beta was also mentioned during a live stream session at The Division’s official Twitch channel.
Earn the Capitol Hill Arm Patch by completing the Invaded Mission in the Private or Open Beta Earn the DC Patriot Weapon Skin by participating in any of the The Division 2 Betas — The Division 2 (@TheDivisionGame) February 7, 2019 Based on the remark made by the developer during the live stream session, the game experience will also likely to be more stable as compared to the closed beta since they clearly intend to implement new fixes for the upcoming open beta. Considering the open beta was only mentioned in passing, we don’t know yet when it will take place though. The Division 2 itself will launch on 15 March, so chances are that the open beta session will be held very soon. (Source: Massive / Twitter, Twitch via GameSpot)
