Excel 2007 Power Programming with VBA (Mr. Spreadsheets Bookshelf)

You need to be aware of several categories of potential compatibility problems. These are listed here and discussed further in this chapter:

• File format issues: Workbooks can be saved in several different Excel file formats. Earlier versions of Excel might not be able to open workbooks that were saved in a later version's file format. For more information about sharing Excel 2007 files, see the sidebar, "The Office 2007 Compatibility Pack."

• New feature issues: It should be obvious that a feature introduced in a particular version of Excel cannot be used in previous versions of Excel.

• Microsoft issues: For whatever reason, Microsoft itself is responsible for some types of compatibility issues. For example, as I note in Chapter 23, index numbers for shortcut menus have not remained consistent across Excel versions.

• Windows versus Macintosh issues: If your application must work on both platforms, plan to spend lots of time ironing out various compatibility problems.

• International issues: If your application will be used by those who speak another language, you must address a number of additional issues.

After reading this chapter, it should be clear that there is only one way to ensure compatibility: You must test your application on every target platform and with every target version of Excel. Often, this is simply not feasible . However, there are measures that you, as a developer, can take to help ensure that your application works with different versions of Excel.

If you plan to share your Excel 2007 application with others who haven't upgraded to Excel 2007, you have two choices:

• Always save your files in the older XLS file format.

• Make sure the recipients of your files have installed the Microsoft Office Compatibility Pack.

The Microsoft Office Compatibility Pack is a free download available at http://www.microsoft.com. When installed, Office XP and Office 2003 users can open, edit, and save documents, workbooks, and presentations in the new file formats for Word 2007, Excel 2007, and PowerPoint 2007.

Keep in mind that this compatibility pack does not endow earlier versions of Excel with any of the new features in Excel 2007. It simply allows those users to open and save files in the new file format.