The item level of dropped gear depends on the difficulty of the dungeon and the level of the character. At level 70:
To queue for Heroic Dungeons through the Dungeon Finder, you must be item level (342), but you can walk in with a pre-made group at any point.
Level requirements for Dragonflight dungeons are simple. For leveling and Normal mode you need to be level 60 or above. For Heroic, Mythic, and Mythic+ modes you must be level 70. This applies to all Dragonflight Dungeons.
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