How to understand the version number
Microsoft Office products use the following syntax for the version number in the About dialog box:
aa.bbbb.cccc
This number represents three items:
- aa: The version of Office.
- bbbb: The version of the program executable file. For example, the Excel.exe file.
- cccc: The version of the Mso.dll file.
Important
- When you install a service pack, the About Microsoft Product name dialog box adds the letters "SP" and the number of the service pack level. How these letters appear depends on the version of the Mso.dll file.
- Because not all updates change the version number that is listed in the About Microsoft Product name dialog box, you must verify the properties for the program’s executable file.
Reference: http://support.microsoft.com/kb/291331
