Party Sync
Party Sync is a feature that lets players having vastly different levels still be able to group and quest together. The higher-level players can party sync in order to reduce their level to the one of the lowest-level players, play the same quests as them even if they already completed once and still get an appropriate reward. Skills, levels, abilities, and systems such as Azerite traits are all adapted or disabled automatically.[1]
Levels will be scaled down to the cap of the expansion content your lowest-level party member qualifies for. As an example, if your lowest-level player is level 83, your level will be scaled down to level 90. However, if they're level 21, your character will be scaled down to level 60. This functionality is restricted to party groups, thus you cannot sync down a whole raid group to run old raids. It does work with dungeon and battleground queues though. The scaling system works with the following brackets:
- Original World of Warcraft:* level 1 to 60.
- The Burning Crusade: level 60 to 80.
- Wrath of the Lich King: level 60 to 80.
- Cataclysm: level 80 to 90.
- Mists of Pandaria: level 80 to 90.
- Warlords of Draenor: level 90 to 100.
- Legion: level 100 to 110.
*Cataclysm low-level content.
Replaying a quest with Party Sync may reward a 
[Salvaged Cache of Goods].
Recruit A Friend
Recruiters who play with their recruits via Party Sync will be able to complete the following quests and earn rewards:
[1-70] Storied Partnerships- [1-70] Dungeon Adventure
- [1-70] Battleforged Team
Patch changes
Patch 8.2.5 (2019-09-24): Added.
See also
- C_QuestSession - Party sync API.