NPOI 2.8.0 Release Notes

[tonyqus]

Release Date: Apr 6, 2026

Important

To ensure the long-term sustainability of this project, a monthly maintenance fee has been introduced. This fee is required to be paid by all organizations or users of any library from this project who generate revenue. You can pay the fee via GitHub Sponsors.

To enact this, an EULA on binary releases is added to the repo and nuget packages that requires payment of the maintenance fee.

For more information on who must pay the fee and other frequently asked questions, please see the Open Source Maintenance Fee organisation page.

What's New in NPOI 2.8.0

CICD/Package Update

• Replace SixLabors.Fonts with SkiaSharp for text measurement #1717
• Replace SixLabors.ImageSharp with SkiaSharp #1718
• Upgrade SkiaSharp to 3.119.2 #1719
• Fix Windows CI: stop TestTempFile from deleting shared temp directory #1746
• Remove NSax to avoid potential licensing issues #1702
• Remove [Platform("Win")] from TestVBAMacroReader; fix AutoSizeColumn on Linux #1715
• Apply Open Source Maintainence Fee EULA to NPOI Binary release #1770
• Remove Nugetizer since it always ignore PrivateAssets setting for SkiaSharp #1771
• Add MSBuild target to check OSMF EULA acceptance tag #1786

Features/Enhancement

• [Experimental] Add ToDataTable and ToDataSet feature #1705
• Add maxRows parameter to ISheet.AutoSizeColumn method.  #1716
• Add support for XDDF #1521
• Integrate XDDFChart into XSSFDrawing #1733
• XWPFChart implementation - Phrase I #1735
• XLookup Function Code Sync from POI #1767
• Implement Area Chart based on XDDF #1773
• Developer Friendly Api Implementation I #1776

Performance Improvement

• Sheet Lazy Loading Implementation #1741
• Implement the larger I/O buffers optimization for SXSSF #1749
• Perf: use Stream.CopyTo and zero-copy MemoryPackagePart reads #1743
• Cache XSSFSheet.MergedRegions to eliminate repeated XML parsing #1744
• Lazy-load SharedStringsTable with streaming parser, dirty tracking, and allocation reduction #1728
• Add UseXmlReader Switch to ShardStringTable #1740
• Fix volatile correctness in lazy load and add roundtrip test #1747
• Implement lazy loading for xl/styles.xml in XSSFWorkbook #1731
• Replace SortedDictionary with Dictionary in HSSFRow, XSSFRow and SXSSFRow #1753
• Implement the larger I/O buffers optimization for SXSSF #1749
• Cache XSSFRow.FirstCellNum/LastCellNum to avoid O(n) LINQ scans #1745
• Restore sorted cell iteration order with lazy cache #1759
• Add caching to XSSFCell numeric and rich string value access #1754

Benchmark Enhancement

• Add LargeExcelFileBenchmarkXSSFReaderLoad method #1701
• Add LargeSSTBenchmark #1729
• Add LargeStylesBenchmark with deterministic HugeStyles.xlsx generator #1730

Bug FIxes

• XSSFTable.CreateColumn return System.ArgumentOutOfRangeException: Index was out of range #1384
• Fix unable to set mutiple print area in HSSF #1706
• Remove duplicate ST_OnOff definition in Math.cs #1713
• Fix CSE array formula evaluation: count booleans in arithmetic operators #1720
• Rounding errors are boosted by ROUNDDOWN, VLOOKUP, etc. #1457
• Fix HSSFSheet.ShiftRows: PhysicalNumberOfRows not decreasing when shifting rows up #1707
• Fix phone number format: escaped dashes misidentified as grouping chars; decimal cast in special format classes #1710
• NPOI does not format simple phone number format correctly #1668
• AutoSizeRow fix for WrapText #1774
• Fix 256× unit mismatch in WrapText auto-row-height calculation #1790

POI Bug Fixes

• POI Bug 69583 - when copying cells with dates - prefer using the numeric data directly #1724
• POI Bug 64986 - Match function cannot evaluate formulas with extra comma before missing optional parameter #1725
• POI Bug 58468 - Implement Days function #1727
• POI Bug 66187 - MS document is error by XWPFDocument to write when XWPFRun call method getTextHightlightColor() or getEmphasisMark  #1723
• POI Bug 63842 FractionFormat casts whole part of the value into 'int' #1726
• Some patches from poi #1711
• POI Bug 51037 - apply default column style if no style set #1781
  Bug 61882 - Some paths can create an XSSFColor instance with a null CTColor reference
  Bug-61906 add API for working with RichStringText and deprecate API methods that use CTRst
  Bug 61859: support for evaluating comparison operators in array mode, detect array mode from formula ptgs
  Bug 61869: updating a cell with shared formula produces an unreadable file
  Bug 61798: Fix usage of getLastCellNum()
  Bugzilla 61116: Formula evaluation fails when using matrix addition within index function call