What’s new

24 September 2026 — Optional formatting preservation

Keep original formatting is now available in Append Rows, Side-by-Side Columns and Preserve Sheets. The option starts off and is available only when every selected input and the output are XLSX.

• Supported colors, fonts, borders, number formats, dimensions, merged cells and selected workbook structures can be retained.
• Unsupported advanced structures can stop formatting-aware processing without producing partial output. Leave formatting off to use the compatibility route.
• Spreadsheet processing remains in the browser. The formatting route loads a same-origin browser Worker and WebAssembly module when needed.
• Ordering, duplicate worksheet names and supported internal-reference relocation were improved. These corrections can change some edge-case results compared with older output.
• This release does not claim to preserve every Excel feature or every formula in every merge mode.