The difference between xls and xlsx in excel

The differences between xls and xlsx are: 1. xls is a binary file format, while xlsx is an XML-based file format; 2. xls can still be opened and edited in newer Excel versions, while xlsx can only be opened and edited in newer Excel versions. Open and edit in; 3. xls does not support some newer functions and features, while xlsx supports more functions and features; 4. xls data is relatively easy to be infected by viruses or malware, while xlsx data is relatively safer.