Live Update 27 brings changes to nearly every piece of XML for the interface. However most of the changes require no updates by authors. You'll notice some numbers next to every piece of text in the xml. These numbers allow SOE to track the text for localization purposes.
Authors please check out my live server compare
here. Nothing has changed since my test compare done on 8/30/06.
*** Headlines ***- Get more from your practicing your craft with new Tradeskill Work Orders!
- The hand of the gods can be felt with two new Live Events!
- Be rewarded with more experience as a solo or raid player!
- Assassins, Bruisers, Defilers, and Troubadors: Get your shiny new profession hats!
Full LU27 Patch Notes