https://www.gamespot.com/articles/destiny-2-servers-down-for-maintenance-before-new-/1100-6455381/

Destiny 2 will be unplayable for a few hours today as developer Bungie performs server maintenance. The company is taking the game offline for around three hours to perform the maintenance, which applies to PS4, Xbox One, and PC. It's in order to prepare the game for the launch of Destiny 2's Curse of Osiris DLC. [Update: Maintenance is officially underway. We'll report back when servers are back online or if there are any changes to Bungie's stated schedule.]

Curse of Osiris costs $20 / £17 / AU $30, and is included in the $35 / £30 / AU $50 Expansion Pass. It introduces a new planet, Mercury, for players to visit, along with new story missions, Strikes, Crucible maps, weapons, armor, and more--you can see some of the new gear in the video above. The expansion's release will coincide with the first of two big December updates. December 5 will also mark a change to Guided Games and the weekly reset schedule, and it will also see the release of PS4 Pro and Xbox One X enhancements for Destiny 2.