This is an older Excel Spreadsheet format (Excel 97-2003). It will open in modern Excel versions, but may trigger compatibility warnings.
Here is a helpful guide to handling this file safely and efficiently: 1. This is an older Excel Spreadsheet format (Excel 97-2003)
If you open the file and Excel asks to "Enable Content" or "Enable Macros," select No unless you absolutely trust the source. Malicious macros are a common way to install malware. 2. Contextualizing the File ( .xls ) This is an older Excel Spreadsheet format (Excel 97-2003)