World of Warcraft v2.1.2 to v2.1.3 US Patch

Description
One highlight is the mail feature that has been 2.5 years in the making...

World of Warcraft Client Patch 2.1.3

General

Read in-game mail will now be kept for thirty days instead of three.
The Warlock spell Incinerate has had the performance of its graphical spell effect improved.
The "Show Launcher" option has changed so that it now defaults to "On". Players will now see the launcher when running WoW by default.

User Interface

Improved the performance of conditional macros, slightly increasing the framerate.
Fixed a crash triggered by many unit frame AddOns.

Bug Fixes

Fixed an issue with the movement of Archimonde's Doomfire.
Fixed the wand missile art on most Shadow based wands to show the correct graphical effect.
Infinity Blades will now despawn properly when the encounter with Kael'thas resets after a wipe.
Gan'arg Underlings and Felhound Defenders are now properly classified as demons.