Excel - True/False showing as 1/0 - Transition Formula Evaluation (Lotus 1-2-3)
Under Options >> Advanced, uncheck 'Transition formula evaluation'. See Excel's Advanced Options.
Turns out this is allows one to "[open and evaluate] Lotus 1-2-3 files without losing or changing information". Lotus 1-2-3 was actually the first computer class I ever took as a teenager!
IBM discontinued support for Lotus 1-2-3 in 2013. And it looks like Excel 2013 was the last version to read Lotus 1-2-3 files. If you still have Lotus 1-2-3 files, you may have luck trying to open/convert them in LibreOffice,then saving as an Excel file.