Latest Patch makes minor changes...
The latest patch release makes a change to the way mail is delivered. Mail including money will now have the 1 hour delay that is in effect for mailing items (Auction House mail is still instantaneous though.) Read mail will also be kept 30 days instead of 3.
In other Patch notes: Your Launcher will now default to ON. So you will now see it when you launch WoW by default. Improved macro performance by increasing the framerate of conditional macros. Crashes triggered by Unit Frame addons will no longer crash.
For more detailed notes visit The Official Patch Notes