Working with Other Versions of Excel
Excel 2010 workbooks use the .xlsx file extension. Excel 2010 is based on Office Open XML formats (but you do not need to know how to use XML to work in Excel 2010).
The reasoning behind this change is because XML helps keep workbooks safer by
- Separating files containing macros or scripts.
- Keeping workbook sizes smaller.
- Helping to prevent data corruption and loss by making workbooks less susceptible to damage.
Opening Workbooks Created in Previous Excel Versions
You can open workbooks that were created in previous versions of Excel. When you open such a workbook, it will open in Compatibility Mode.
Saving an Excel File Created in a Previous Version
When you save a file that was created originally in a preview version of Excel, the Save As dialog box will open automatically, to save the file with an .xlsx file extension.
Saving an Excel File as a Previous Version
Also, when you save an Excel 2010 file as a previous version, Compatibility Checker will identify any new features that will not work in that version.