We’re happy to announce the release of GroupDocs.Comparison for .NET v26.10, available as of October 2026. This release introduces OCR-based image comparison — comparing images by recognized text rather than pixel data — along with major fixes and enhancements for spreadsheet comparison, including performance improvements and correct handling of row heights, numeric cell types, and deleted rows. Additional improvements span PDF, Word, TXT, and HTML comparison results.

What’s new in this release

  • COMPARISONNET-4844 | Feature | Compare images by recognized text (OCR)
  • COMPARISONNET-4944 | Feature | Support HighlightColor in StyleSettings for spreadsheet comparison
  • COMPARISONNET-4945 | 🔧 Fix | Fix XLSX comparison taking minutes even for identical files
  • COMPARISONNET-4940 | 🔧 Fix | Fix one deleted row marking every following row as changed in XLSX comparison
  • COMPARISONNET-4946 | 🔧 Fix | Preserve auto-height rows instead of forcing a fixed 15 pt height in XLSX result
  • COMPARISONNET-4947 | 🔧 Fix | Preserve the numeric cell type in the spreadsheet comparison result
  • COMPARISONNET-4943 | Enhancement | Avoid replacing short text strings entirely in Excel comparison
  • COMPARISONNET-4931 | Enhancement | Show replaced text as deleted and then inserted in PDF comparison
  • COMPARISONNET-4927 | Enhancement | Normalize the order of deleted and inserted components in TXT comparison output
  • COMPARISONNET-4935 | Enhancement | Remove temporary path usage from HTML preview generation
  • COMPARISONNET-4936 | 🔧 Fix | Fix PageNumbers property being ignored in PreviewOptions when rendering HTML files
  • COMPARISONNET-4926 | 🔧 Fix | Fix document comparison crash when comparing Word documents with tables
  • COMPARISONNET-4923 | 🔧 Fix | Fix lost line breaks in the HTML result of text comparison
  • COMPARISONNET-4917 | Enhancement | A set of internal improvements

Public API changes

A new OcrOptions class has been added to the GroupDocs.Comparison.Options namespace and is exposed through the new CompareOptions.Ocr property.

Member Type Description
Enabled bool true to compare the recognized text; false to compare the images by their pixels. Default is false.
DisplayMode OcrDisplayMode How the comparison result is laid out. Default is OcrDisplayMode.SideBySide.
Language OcrLanguage The language or script the documents are written in. Default is OcrLanguage.Latin.
DisableResourceDownloads bool true to fail when a required recognition model is not available locally; false to download it. Default is false.
ResourcesPath string The folder that contains the recognition models, or null to use the default location.

The new OcrDisplayMode enum controls how the result of comparing the recognized text is laid out:

Value Description
SideBySide Default mode. Produces an image showing the source and the target side by side, each marked where it differs from the other, with the original layout of both preserved.
Text Produces an image showing the recognized text of both documents as plain text, with deleted and inserted words highlighted. The layout of the original documents — fonts, tables, columns and images — is not reproduced.

New features

Compare images by recognized text (OCR)

GroupDocs.Comparison can now compare images by the text recognized in them instead of by their pixels. Previously, comparing two images meant comparing them pixel by pixel — a scan shifted by a few pixels, re-saved at a different quality or produced by a different scanner reported differences everywhere. With OCR comparison enabled, the text is recognized on both images first and then compared as text, so the result shows the actual wording that changed.

This makes it possible to compare scanned contracts, screenshots, photographed documents and other image-only files in a meaningful way.

Note: OCR comparison is not available for .NET Framework.

Support HighlightColor in StyleSettings for spreadsheet comparison

The HighlightColor property of StyleSettings is now applied when comparing spreadsheets, so the background color used to mark changed cells can be customized the same way as for other formats.

Code example

To enable OCR-based comparison with side-by-side layout:

using (Comparer comparer = new Comparer("source.png"))
{
    var options = new CompareOptions
    {
        Ocr = new OcrOptions
        {
            Enabled = true,
            DisplayMode = OcrDisplayMode.SideBySide
        },
        GenerateSummaryPage = false
    };

    comparer.Add("target.png");
    var result = comparer.Compare("result.png", options);
}

To get a plain-text result and use Cyrillic language models from a local folder:

using (Comparer comparer = new Comparer("source.png"))
{
    var options = new CompareOptions
    {
        Ocr = new OcrOptions
        {
            Enabled = true,
            DisplayMode = OcrDisplayMode.Text,
            Language = OcrLanguage.Cyrillic,
            ResourcesPath = @"C:\ocr-models",
            DisableResourceDownloads = true
        },
        GenerateSummaryPage = false
    };

    comparer.Add("target.png");
    comparer.Compare("result.png", options);
}

To customize highlight colors in spreadsheet comparison:

using (Comparer comparer = new Comparer("source.xlsx"))
{
    comparer.Add("target.xlsx");

    var options = new CompareOptions
    {
        InsertedItemStyle = new StyleSettings { HighlightColor = Color.LightGreen },
        DeletedItemStyle  = new StyleSettings { HighlightColor = Color.LightPink }
    };

    comparer.Compare("result.xlsx", options);
}

How to get the update

NuGet

Upgrade to the latest GroupDocs.Comparison package via NuGet:
GroupDocs.Comparison 26.10.0

Install via .NET CLI:

dotnet add package GroupDocs.Comparison --version 26.10.0

Direct download

Download assemblies from the GroupDocs.Comparison for .NET 26.10 Release Notes page.

Resources