Below you can see a changelog, which was made on 5.4.2 for one week, from 26.02.14 to 05.03.14:

General:

- Rewrited network code on Boost.Asio.
- Fix increase limit of Currency points depending on arena rating.
- Fix locale for many npc texts.
- Fix bug, when spell http://www.wowhead.com/spell=134735 not work in some times on arena and bg.
- Now pets correct remove if using fly mounts and summon after landing on the ground.
- Fix bug, when in some times, after use mounts, character decreases in size.
- Fix show arena/bg unit frames.
- Fix currency returning after items refund to vendor.
- Fix 3 memory leak.
- Fix 4 reasons of server crash.

Dungeons and Raids:

- Implemented raid Onyxia Lair.

Imlemented new Cataclysm dungeons and raids:

The Stonecore.
Grim Batol.
Throne of the Tides.
Hour of Twilight.
The Bastion of Twilight.
The Vortex Pinnacle.
Blackrock Caverns.

Spells:

Druid:

- Fix spell http://www.wowhead.com/spell=145138.
- Fix up character stats in form http://www.wowhead.com/spell=5487.
- Fix bug, when http://www.wowhead.com/spell=33786 can remove by mass-dispel.
- Fix bug, when set bonus http://www.wowhead.com/spell=23218 summable with talent http://www.wowhead.com/spell=131768.
- Fix spell http://www.wowhead.com/spell=102280.
- Fix talent http://www.wowhead.com/spell=145108.
- Fix http://www.wowhead.com/item=43335.
- Fix http://www.wowhead.com/item=40906.
- Fixed bugs with spells from the previous update.

Warrior:

- Now spell http://www.wowhead.com/spell=85288 can have 2 charges.
- Now you can not disarm the warrior, when he use spell http://www.wowhead.com/spell=46924.
- Fix slow effect by spell http://www.wowhead.com/spell=12292.
- Now spell http://www.wowhead.com/spell=86346 gives correct ignoring armor.
- Fix bug, when in PvP http://www.wowhead.com/spell=29838 healed much less.
- Now with active spell http://www.wowhead.com/spell=46917, you can use also Polearms.

Paladin:

- Fix spell damage increase http://www.wowhead.com/spell=114157 from other spells.
- Fix http://www.wowhead.com/item=41102.

Warlock:

- Fix talent http://www.wowhead.com/spell=108415.
- Fix scaling of armor for warlock pets from owner.
- Fixed bugs with spells from the previous update.

Priest:

- Now, if with cast spell http://www.wowhead.com/spell=8092 proc http://www.wowhead.com/spell=109175, after cast, not set cooldown.

Shaman:

- Fix totems model.