Build 3.0.0.77 of xlsgen makes it possible to read XLSX files that have a benign invalid internal ZIP table of contents, particularly when there is a discrepancy between the compact file's last modification date, and the table of contents file entry's last modification date. Usually this is the case when a ZIP file is modified outside a proper ZIP library.

xlsgen mimics the behavior of Excel, which is to ignore the invalid nature of the ZIP structure.