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Adobe PDF Library 21

Release Notes

Adobe PDF Library v21 Release Notes - This page lists updates, fixes, changes and enhancements made to the Adobe PDF Library v21 provided by Datalogics.

APDFL v21.0.0P1f (October 30, 2026)

New Features:

  • Rendering to a CMYK target colorspace can now preserve K-only content. A new rendering flag kPDPagePreservePrimariesK has been added to the C/C++ interface, and a new DrawFlags enumeration value PreservePrimariesK to the Modern C++, .NET and Java interfaces. This enhancement allows content originally defined using only the black (K) channel to remain K-only when rendering to a CMYK target colorspace, rather than being converted into a combination of CMYK components. Preserving K-only content helps maintain color consistency and improves output quality, particularly in printing workflows where accurate black reproduction is important.
  • Office-to-PDF (Microsoft Word DOCX to PDF) is now available through the Adobe C/C++, NuGet and Maven packages. Previously available only through the Modern C++ interface, this functionality has been extended to support the Adobe C/C++, .NET, and Java interfaces. Developers can now incorporate Microsoft Word DOCX to PDF conversion directly into their applications across these supported APDFL interfaces, providing greater flexibility and consistency across different development environments.
  • DLI Now Available for APDFL v21.0.0 — This release is designed to work across all APDFL v21.0.0 builds without requiring a version-specific DLI update. This provides greater flexibility when upgrading to newer APDFL v21.0.0 builds and simplifies deployment and maintenance by eliminating the need to obtain a matching DLI version for each update.

Changes:

  • Office-to-PDF is now delivered as an Adobe PDF Library plug-in. The office_to_pdf_sdk library and the office_to_pdf/converter.hpp header have been retired; applications built against the previous release must be updated to use the plug-in interface. Office-to-PDF is supported on Windows x64, Linux x86_64 and aarch64, and macOS arm64.
  • Corrects embedded time-stamping for CMS and PAdES signatures. Per RFC 3161 Appendix A, the timestamp now covers the signature value rather than the document bytes. Plain timestamp signatures continue to cover the document bytes.
  • APDFL.SharedLibs package updated to 21.5.0.
  • Adobe.PDF.Library.Resources package has been updated to 1.1.1, adding the math font used by Office-to-PDF output.
  • With this release, the NuGet package version has been increased to 21.5.0.
  • With this release, the Maven package version has been increased to 21.5.0.

Open Source Updates:

  • Expat 2.9.0 — mitigates CVE-2026-102633 and CVE-2026-77214.
  • cURL 8.23.0 — fixes CVE-2026-92392 (high severity; a use-after-free during HTTP/2 uploads), along with 20 other lower-severity vulnerabilities.

Problem Corrections:

  • Fixes a crash that could occur optimizing a document with a DeviceN image in some cases.
  • SF47440 – Corrects a problem where the WordFinder Quad coordinates of right-to-left text could be incorrect in some cases.
  • SF47458 – Support for flattening XFA documents with buttons using a Join style of Round has been improved (Forms Extension).
  • SF47739 – Corrects a problem flattening an XFA document with a TextEdit field using RichText shared across pages, with regard to complicated expressions of individual vertical spacing.
  • SF47740/SF47769 – Corrects a case where rendering to a CMYK target colorspace changed unexpectedly for documents with K-only content. See the new PreservePrimariesK flag under New Features.
  • SF47756 – Corrects a problem flattening XFA documents regarding handling of checkButton fields using boolean items (Forms Extension).
  • SF47757 – Corrects a problem where flattening XFA documents with DateTime fields would not preserve their formatting in some cases (Forms Extension).
  • SF47759 – Corrects an issue where XFA fields meant to be included in AsIfPrinted could be excluded when flattened in some scenarios (Forms Extension).
  • SF47760 – Adds support for flattening fields using captions that have inline placement (Forms Extension).
  • SF47761 – Corrects a problem where flattening XFA documents with NumericEdit fields would not preserve their formatting in some cases (Forms Extension).
  • SF47768 – Corrects a crash that could occur with PDFileAttachmentSetAFRelationship() in some cases.

APDFL v21.0.0PlusP1e (October 6, 2026)

New Features:

  • PDF/X-4p Conversion Support — Added support for PDF/X-4p conversion, providing additional flexibility for PDF/X workflows that use externally referenced ICC color profiles. This allows color profiles to be managed separately from the PDF while still supporting standardized print production requirements. Customers can use this option in workflows where shared or centrally managed color profiles are preferred.
  • PDF/X-5pg Conversion Support — Added support for PDF/X-5pg conversion, providing additional flexibility for print workflows that use both externally referenced graphical content and externally referenced ICC output profiles. This can support production environments where high-resolution graphics and color profiles are managed separately from the primary PDF file. Customers can use PDF/X-5pg to streamline workflows that rely on shared external resources while maintaining PDF/X compliance for professional print production.
  • New ConvertWordToPDF Sample (Modern C++) — A new sample demonstrating Microsoft Word (DOCX) to PDF conversion through the Office-to-PDF Plugin is now available for the Modern C++ interface. The sample provides a practical reference for integrating Word-to-PDF conversion into C++ applications and shows how developers can use APDFL together with the Office-to-PDF Plugin to incorporate DOCX conversion into automated document-processing workflows. The sample can serve as a starting point for applications that need to convert Microsoft Office content before performing additional PDF processing, helping reduce implementation effort by providing a working example of the conversion workflow. This sample is currently available only for the Modern C++ interface, with support for additional interfaces planned for a future release.

Changes:

  • Component versions aligned to v4 across Modern C++, Web-to-PDF, and Maven Builder.
  • Hardened the optimizer against crashes on crafted input.
  • Added the missing SBOM for the OCR subsystem.
  • Online documentation corrections.
  • With this release, the NuGet package version has been increased to 21.4.0.
  • With this release, the Maven package version has been increased to 21.4.0.

Open Source Updates:

  • Expat 2.8.5
  • OpenSSL 3.6.4

Problem Corrections:

  • SF47547 – Resolves a native memory leak that could occur when repeatedly flattening XFA files with Forms Extension.
  • SF47638 – convertToWord() now raises "Operation Not Permitted" on PDF-to-Office conversion failures with encrypted PDFs.
  • SF47682 – Corrects a hang caused by a malformed PDF with a circular page tree.
  • SF47686 – Corrects a Forms Extension regression (from 21.0.0P1c) where elements in XFA forms were left unflattened.
  • SF47687 – Corrects a Forms Extension regression (from 21.0.0P1c) where form elements were not hidden when flattening in print mode.
  • SF47688 – Corrects a case where text did not appear bold when flattened with "Arial Black" in the fonts directory.
  • SF47717 – Corrects a "Font Not Found" error in the ContentCreation .NET sample on Linux ARM.
  • SF47724 – Corrects a color-conversion change; adds a new mPromoteOnlyDeviceGrayToCMYK option.
  • SF47726 – Corrects a regression (from 21.0.0P1d) where text could be partially cut off (Java).
  • SF47730 – Limits FamilyName cache fallback for non-standard styles.
  • SF46760 – Corrects handling of system-font create and embedding-protection flags so fonts marked non-embeddable are reported and handled correctly.

APDFL v21.0.0PlusP1d (September 4, 2026)

New Features:

  • Brotli Compression Support — Added support for Brotli compression when saving PDF files through the new PDSaveAddBrotli flag. Brotli can help reduce PDF file sizes by providing more efficient compression for supported stream data, which can improve storage efficiency and reduce transfer times.
    This capability is based on a PDF Association extension to PDF 2.0 and is not part of the ISO 32000-2:2020 standard. PDF processors which do not support this extension may be unable to read Brotli-compressed streams.
  • Tagged PDF Support in Web2PDF — Added tagged PDF support to Web2PDF for improved accessibility. Tagged PDFs include structure information that screen readers and other assistive technologies use to read a document in the correct order. This makes the PDFs Web2PDF generates accessible to users with disabilities and helps meet accessibility requirements.

Changes:

  • The WebToPDF plugin is now included in the APDFL NuGet package (Windows x64/ARM, Linux x64/ARM, macOS ARM), with a new CreateDocFromWebPage sample.
  • Corrected an issue flattening XFA documents where checkbox fields with non-zero margins could be slightly cropped when using Forms Extension.
  • OCR data-only NuGet packages no longer pin specific target frameworks.
  • With this release, the NuGet package version has been increased to 21.1.0.
  • With this release, the Maven package version has been increased to 21.1.0.
Important note on Java package distribution: Starting with v21.1.0, APDFL Java packages are no longer published to Maven Central and are now available through the Datalogics Maven repository. Customers using Maven or Gradle should update their build configuration to reference the Datalogics repository when resolving APDFL Java dependencies.Download Maven Configuration Guide for detailed setup instructions, or visit the Java Getting Started page for a quick setup guide.

Open Source Updates:

  • Expat 2.8.3 (addresses CVE-2026-7522)
  • giflib 6.1.3 (addresses CVE-2026-26740)

Problem Corrections:

  • SF47594 – Corrects an issue during PDF/A conversion that could leave fonts unembedded when problematic fonts were encountered.
  • SF47595 – Corrects a problem where converting to PDF/A Part 2 or later could leave Optional Content (layers) misconfigured.
  • SF47641 – Corrects an issue where fonts using WinAnsiEncoding could be unnecessarily recreated during PDF/A conversion.
  • SF47643 – Corrects a problem where re-subsetting Type 1 fonts could result in missing glyphs.
  • SF47650 – Corrects a problem where applying a redaction to an image could unexpectedly affect the same image reused elsewhere.
  • SF47659 – Corrects a problem when long paths are used on Windows for temporary files.
  • SF47664 – Corrects a case where the Optimizer Report could indicate an incorrect previous image size.
  • SF47680 – Corrects a color-conversion error when nested Form objects are present.
  • SF47681 – Resolves a memory leak in PDSysFontAcquirePlatformData().
  • SF47683 – Corrects a stack overflow that could occur parsing a crafted PDF with deeply nested Forms.
  • SF47684 – Corrects a crash that could occur rendering a page with an invalid JBIG2 image.

APDFL v21.0.0PlusP1c (July 19, 2026)

New Features:

  • Added support for OCR with Vietnamese text.
    Optical Character Recognition (OCR) now supports recognition of Vietnamese-language text, including Vietnamese-specific characters and diacritical marks. This enhancement improves text extraction accuracy and searchability for scanned documents containing Vietnamese content.

Changes:

  • Forms Extension installers now support the Modern C++ interface.
  • The XPS2PDF plugin now reports a specific error when the joboptions file cannot be found.
  • Corrected installer documentation that still referenced APDFL 18.
  • With this release, the Maven package version has been increased to 21.0.1.
  • With this release, the NuGet package version has been increased to 21.0.1.

Open Source Updates:

  • Boost 1.91.0
  • cURL 8.21.0
  • Expat 2.8.2 (addresses CVE-2026-45186)
  • libTIFF 4.7.2
  • OpenSSL 3.6.3

Problem Corrections:

  • SF45180 – Improves flattening of XFA documents where a Button field has no Caption but a Text Label overlaid on top of it.
  • SF47401 – Corrects an issue where content could be clipped unexpectedly when flattening an XFA document with Forms Extension.
  • SF47460 – Corrects an issue where some XFA documents, when flattened AsIfPrinted, showed content that was meant to be excluded.
  • SF47461 – Corrects an issue where a heavily crowded Text Field shared across pages of an XFA document could be slightly clipped when flattened with Forms Extension.
  • SF47486 – Improves flattening of XFA documents where a Button field has no Caption but a Text Label overlaid on top of it.
  • SF47555 – Corrects a problem where System Font selection could choose a similarly named but different style variant in some cases.
  • SF47562 – Corrects an issue preserving the grouping symbol in a decimal value for a numericEdit field when flattening an XFA document.
  • SF47581 – Corrects a problem where rendering a document with minor Page Content errors raised an error when it previously did not.
  • SF47585 – Corrects a small memory leak that could occur when subsetting fonts.
  • SF47591 – Corrects an issue where a PDF's Producer property still reported APDFL v18; it now correctly reports v21.
  • SF47597 – This corrects a problem during Color Conversion where the inherited GraphicState would be changed unexpectedly in some cases.
  • SF47599 – Corrects an issue where rendering to a CMYK-based space would not preserve K-only content as pure black.
  • SF47603 – This corrects an issue with the Color Conversion option mPromoteGrayToCMYK when enabled, which would result in unexpected Gray values.
  • SF47610 – This corrects a problem where Color Converting a Page could unexpectedly affect a shared Form on another page.

APDFL v21.0.0P1b (May 22, 2026)

Datalogics is pleased to announce the release of APDFL v21.0.0Plus1b. This release is a major upgrade built on the Adobe PDF Library (PDFL) v21.0 core libraries and includes a wide range of new features, performance improvements, compatibility enhancements, and problem corrections.

.NET and Java interfaces are not included in the APDFL v21.0.0Plus1b release. Support for these interfaces are planned for a future update.

New Features:

  • Modern C++ SDK — Built on the same APDFL runtime as the existing integration libraries, the Modern C++ SDK provides a C++17-based interface featuring RAII-based resource management, exception-driven error handling, move semantics, std::unique_ptr / std::shared_ptr ownership models, strongly typed flags, and a unified datalogics_interface namespace. These enhancements reduce boilerplate code, simplify resource management, and enable more natural integration of PDF functionality into modern C++ applications.
    The Modern C++ SDK requires a C++17 compiler and is supported on Windows (MSVC 19.3+ / Visual Studio 2022 v143 toolset, x64 and ARM64), Linux Rocky 9+ (Clang 18+ with libstdc++11, x86_64 and aarch64), and macOS 15+ (Apple Clang 16.4+ / Xcode 16+, x86_64 and arm64).
    The existing APDFL C++ interface will now be referred to as "Adobe C/C++" and remains fully supported. Existing integrations can continue unchanged, and migration to the Modern C++ SDK is optional.
  • WebToPDF — A new Plug-In for APDFL that converts an HTML file tree on disk, or a URL, to PDF. Available on Windows 64, Windows ARM, Linux x64, and Linux arm64.
  • Added support for the Chinese GB18030 font — Enables correct rendering and processing of Simplified and Traditional Chinese characters in documents that use GB18030-compliant fonts. This improves compatibility with Chinese-language PDFs and helps ensure accurate display of multilingual text content.
  • New ListStructureTree Sample (Modern C++) — This sample walks the logical structure tree of a tagged PDF document and prints each element's struct type (/S), parent chain, and kid entries (child elements and marked-content references). Available for the Modern C++ interface.

Problem Corrections:

  • SF44603 – Word Finder: Fixed incorrect positioning of Arabic diacritical marks (harakat) in extracted text. In certain PDFs, combining marks such as Damma (U+064F) could be attached to the wrong base character when the diacritic was spatially positioned between two Arabic glyphs with similar overlap.
  • SF46074 – Resolved a problem with WordFinder processing Thai diacritics.
  • SF46900 – Corrects an issue where updating Page Content could cause text contained within Marked Content to unexpectedly be located outside of the Marked Content.
  • SF47417 – Corrects an issue where updating Page Content could cause text contained within Marked Content to unexpectedly be located outside of the Marked Content.
  • SF47421 – Corrects a problem saving a DeviceN rendered image to a TIFF where the TIFFTAG_PHOTOSHOP tag data would be incorrect.
  • SF47454 – Fixes a Stack Overflow that could occur setting Page Content during PDF/A conversion for Property Lists that are improperly defined.
  • SF47481 – Rendering has been improved to be more resilient against problematic content that would previously raise an error. Some error strings that were meant to have a string format specifier used in combination with the non-fatal error argument were missing and have been added.
  • SF47530 – Corrects a problem where converting a document to PDF/A could misinterpret the CTM for an ImageMask in some cases.