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Third-Party Dependencies

Runtime dependency and upstream license notes for the public OfficeIMO package family.

OfficeIMO packages are published under the MIT License , but several packages intentionally build on upstream open-source components. This page exists to make those relationships easier to review during OSS approval, procurement, and redistribution checks.

Scope

  • Covers shipped runtime dependencies for the public OfficeIMO package families documented on this site.
  • Focuses on user-visible dependencies rather than test-only packages, benchmark harnesses, sample apps, or framework/reference-only helpers.
  • Exact package ranges live in the linked .csproj files and NuGet metadata.
  • This page is informational only and is not legal advice.

Package Family Overview

OfficeIMO package or familyUpstream components used in the repo todayWhy they are there
OfficeIMO.WordDocumentFormat.OpenXml [3.5.1, 4.0.0) , SixLabors.ImageSharp 2.1.11OOXML document model, packaging, colors, and image handling
OfficeIMO.ExcelDocumentFormat.OpenXml [3.5.1, 4.0.0) , SixLabors.ImageSharp 2.1.11 , SixLabors.Fonts 1.0.1Workbook model, image support, and font measurement/layout work
OfficeIMO.PowerPointDocumentFormat.OpenXml [3.5.1, 4.0.0)Presentation OOXML model and packaging
OfficeIMO.Word.HtmlDocumentFormat.OpenXml [3.5.1, 4.0.0) , AngleSharp 1.3.0 , AngleSharp.Css 1.0.0-beta.157HTML and CSS parsing for Word conversion workflows
OfficeIMO.Markdown.HtmlAngleSharp 1.3.0HTML parsing for Markdown conversion and bridge scenarios
OfficeIMO.Word.PdfQuestPDF 2026.2.0 , SkiaSharp 3.119.2PDF document layout and graphics rendering
OfficeIMO.VisioSixLabors.ImageSharp 2.1.11 , System.IO.Packaging 10.0.3Image handling plus OPC packaging support for .vsdx files
OfficeIMO.MarkdownNo third-party runtime package referencesCore package is intentionally dependency-light
OfficeIMO.CSVNo third-party runtime package referencesCore package is intentionally dependency-light
OfficeIMO.ReaderComposes first-party OfficeIMO packagesIts effective upstream surface follows the format packages it wraps

Additional Microsoft compatibility helpers may appear on older target frameworks, but the table above focuses on the upstream packages that most teams will care about during license review.

Upstream License Notes

Upstream projectLicense or modelOfficeIMO packages that use itWhat to know
DocumentFormat.OpenXmlMITWord, Excel, PowerPoint, Word.HtmlThis is Microsoft's official Open XML SDK and the main OOXML building block in the Office document packages.
SixLabors.ImageSharp 2.1.11Apache License 2.0Word, Excel, VisioThis is the exact version currently pinned in the repo. If the package line is upgraded in future, re-check the upstream terms rather than assuming the same license model still applies.
SixLabors.Fonts 1.0.1Apache License 2.0ExcelOfficeIMO currently pins the 1.0.1 line. As with other Six Labors packages, review the exact package version you ship instead of assuming newer lines follow the same terms.
AngleSharpMITMarkdown.Html, Word.HtmlUsed for HTML parsing and DOM work.
AngleSharp.CssMITWord.HtmlAdds CSS parsing on top of AngleSharp for HTML conversion flows.
QuestPDF 2026.2.0Community MIT for qualifying cases, paid tiers otherwiseWord.PdfThe official license guide allows MIT/community use for some cases, but larger businesses are expected to purchase a paid license. Because OfficeIMO.Word.Pdf references QuestPDF directly, teams should review the exact QuestPDF license guide for their own usage context.
SkiaSharpMITWord.PdfGraphics and drawing backend used by the PDF conversion layer.
System.IO.PackagingMITVisioMicrosoft packaging primitives for OPC-style containers.

What We Recommend Teams Check

  1. Review the exact PackageReference list for the OfficeIMO packages you ship, not just the repo root license.
  2. Treat QuestPDF as the first dependency to review explicitly during commercial approval, and re-check exact Six Labors package versions whenever they change.
  3. Re-check upstream terms whenever a dependency version changes, especially around PDF and imaging stacks.
  4. Keep a copy of the upstream notices or license URLs in your own release/compliance workflow if your organization requires that.

How We Address This In The Website

  • We keep the first-party OfficeIMO package license visible across the repo and site.
  • We document the public dependency surface here instead of hiding it in project files.
  • We keep the page scoped to real shipped package dependencies so it stays reviewable and current.

If you need the exact current references, start with the repository project files such as `OfficeIMO.Word.csproj` , `OfficeIMO.Excel.csproj` , `OfficeIMO.Word.Pdf.csproj` , and `OfficeIMO.Visio.csproj` .