xlsx file generating error #NAME?

Greetings Excel Gurus. We have a Business Plan that has been working fine until today. When we opened it up today, most all of the formulas were changed with =_xlfn.IFS in the beginning and the cell represents #NAME? instead of the number. HELP! This of course changes all the data in the worksheets. Excel file is 1.4 MB and wont let me upload to forum. Here is a DL link in dropbox.

https://www.dropbox.com/s/nlwmq9sa50...acre.xlsx?dl=1

I cleared the formats and was able to get it below 1MB

IFS——This function is only available in office 365 or office 2019. The formulas should be created by an Office 365 or Office 2019 user. If you run it on a lower version, the result will show error value (#NAME) as your Excel application does not support this formula.
As far as I know, there are 3 options to solve this problem:
1. upgrading your Office software to a higher version.
2. uploading your file to Onedrive and use web browser to open it through office live.
3. change your formulas, using other formulas, such as IF instead.