Although it is already 202X, and Microsoft's Office has been updated to the 202X version, I still use Office 2003 on my computer. Firstly, it is enough to meet my needs, and secondly, it is still simpler, smaller and more efficient than all other higher versions of Office. And this is what AppNee likes and pursues. If you are also using Office 2003 or lower version, then you may also face the same needs as us - use Office 2003 to open file formats like DOCX, XSLX, etc. that have only appeared since Office 2007. To solve this problem, you do not need to install a higher version of Office, just install a file format compatibility pack.