One open() for XLSX, XLS, and CSV: what's new in FastExcelReader 4.2
aVadim
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26.07.2026
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We had barely finished the post about 4.0 when 4.1 and 4.2 shipped. Here is what changed: Excel::open() now detects the format from the file signature and reads XLSX, XLS, and CSV in a single line — no more branching on the file extension.