The Burning Crusade, the first WoW expansion, was published in 2007. Mainly, the updates are not many in terms of game play, the only one that interested this aspect is that the raids have been reduced from 40 to 25 players for make more playable the epic adventures. The updates that comes with The Burning Crusade are:

• Maximum level is now 70; in the original one was 60
• A new continent called Outland (that is the parallel world of Draenor) was added; it contains 7 regions that can be played by characters from level 58 to 70:

1. Hellfire Peninsula,from level 58 to 62
2. Zangarmarsh, from level 61 to 63
3. Terokkar Forest, from level 63 to 65
4. Nagrand, from level 64 to 67
5. Edge Mountains, from level 66 to 68
6. Shadowmoon Valley, from level 67 to 70
7. Netherstorm, from level 67 to 70

• More races added: draenei and blood elves
• Added the flying mounts that can be usable only in Outland
• Introduced the jeweler profession (Jewelcrafting)
• Added the battleground of Eye Of The Storm
• Added new arenas, and the Arena PvP
• Decreased the size of the instance and the maximum number of participants (40 to 25)
• Added more instances and raid
• Introduced Heroic Instance (more difficult than the normal instance)
• The socket (or sockets), a system upgrade of equipment that consists of inserting specific gems (created with jewelcrafting) in the boxes of the weapon or armor.