Jim Thatcher has posted details of the file format options in the next version of Office and its support of IS29500 strict.

From his post, the following table shows the evolution of file format support in the last few versions of Office:

 

Office 2003

Office 2007

Office 2010

The New Office

Binary format
(.doc, .xls, .ppt)

Open, Edit, Save

Open, Edit, Save

Open, Edit, Save

Open, Edit, Save

Transitional
Open XML

Open, Edit, Save

Open, Edit, Save

Open, Edit, Save

Open, Edit, Save

Strict Open XML

   

Open, Edit

Open, Edit, Save

ODF 1.1

 

Open, Edit, Save

Open, Edit, Save

Open, Edit

ODF 1.2

     

Open, Edit, Save

PDF

 

Save

Save

Open, “Edit”, Save

It is definitely worth your time to read his post in detail.