To quote Brian Jones:
As I already mentioned, in the last face to face meeting in Trondheim, Norway we unanimously voted to approve the final draft of the Office Open XML spec as ready to submit to the Ecma General Assembly. The GA will then review the draft and in December there will be a vote to approve it as an Ecma Standard!
This is a huge milestone, and the entire technical committee has worked extremely hard over the past year. We really had an amazing collection of contributors to this standard, and if you take a look, it will show: http://www.ecma-international.org/news/TC45_current_work/TC45-2006-50_final_draft.htm
If you are already receiving 2007 files but are not using the beta yet, perhaps have a look at the beta file compatibility pack.
More on getting the compatibility pack can be found in my previous post on this.