_xlfn.IFS PROBLEM - Microsoft Community
https://answers.microsoft.com/en-us/msoffice/forum/all/xlfnifs-problem/499c4d75-335a-469c-96bd-9b6a3bcc7935
Jan 31, 2018 · So if you open the Excel file in a previous version (including standalone Excel 2016), Excel replaces the function name with _xlfn.IFS. That means Excel recognizes that it is an Excel function, but not a function that is supported by the current version of Excel. As for IFS per se, it is simply shorthand for nesting IF expressions.
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