Pdftools SDK Updates & Release Notes

12 August 2026

Fixed​

• Before this update, the Pdftools SDK could calculate the color complexity of images that use indexed color spaces incorrectly, due to an index overflow and unchecked lookup-table access at the table boundaries. As a consequence, affected indexed images could render incorrectly. With this release, index handling prevents the overflow and lookup-table access is bounds-checked. As a result, indexed images render reliably.
• Before this update, Pdftools SDK for Java could fail to extract its native libraries when the Pdftools SDK JAR file was repackaged into another JAR. As a consequence, the runtime failed to start or load in some environments. With this release, native library extraction handles repackaged JARs correctly, and the extraction flow produces more detailed diagnostic information. As a result, runtime initialization is reliable for repackaged JARs, and loading issues are easier to investigate with Pdftools support.

23 July 2026

Added​

• Indexed (palette-based) PNG output
  Render PDF pages to smaller PNG files, suitable for thumbnails, web previews, and high-volume archiving. With this release, Pdftools SDK supports the PngColorSpace.Indexed color space for PNG output. Instead of a full color value, each pixel stores a short reference into a palette of up to 256 colors. Typical document pages, such as text, tables, and line art, contain only a few distinct colors. They keep their visual quality at a much smaller file size. Choose the palette size using the PngImageOptions.BitsPerPixel property. Indexed output is always opaque. For technical details, such as valid values, defaults, and error behavior, refer to the PngImageOptions API reference for your language:
  • C
  • Java
  • .NET
  • Python

Fixed​ …

9 July 2026

Fixed​

• Before this update, the MRC optimizer removed the cmap and name tables from CID-only OpenType FontFile3 streams, producing font programs that strict OpenType validators rejected, although most viewers still rendered them correctly. With this release, table stripping is restricted to FontFile2 TrueType fonts, so embedded OpenType FontFile3 streams remain spec-compliant after optimization.

• Before this update, the ResolutionDPI and ThresholdDPI settings on the Web and MinimalFileSize optimization profiles affected only color and grayscale images, leaving bitonal images untouched. As a consequence, lowering the target resolution didn’t shrink files that contained high-resolution bitonal images. With this release, these settings also apply to bitonal images when explicitly configured.

• As of this release, Pdftools SDK no longer supports a glibc 2.12 build. The minimum supported glibc version is 2.17. Earlier releases of Pdftools SDK keep their glibc 2.12 build. If you need glibc 2.12 support in a newer releases of Pdftools SDK, contact Pdftools through the Contact page. …

9 July 2026

Fixed​

• Before this update, the ResolutionDPI and ThresholdDPI settings on the optimize-web and optimize-minimal profiles affected only color and grayscale images, leaving bitonal images untouched. As a consequence, lowering the target resolution didn’t shrink files that contained high-resolution bitonal images. With this release, these settings also apply to bitonal images when explicitly configured.

• Before this update, the revocation status of intermediate Certificate Authority (CA) certificates in the signing chain wasn’t reflected in the overall signature validity. As a consequence, a signature backed by a revoked intermediate CA could still be reported as valid. With this release, intermediate CA certificates are validated and their revocation propagates to the overall signature result.

• Before this update, post-analysis failures during PDF to PDF/A conversion were reported with a generic message that didn’t identify the object or page that caused the failure. As a consequence, applications had no diagnostic information to surface. With this release, the message includes the failing object ID, page number, and a count of any additional recorded errors.

26 May 2026

Added​

• Page-consumption reporting in verbose mode
  In verbose mode (-verbose), the Shell Tool prints the number of pages charged for the current conversion. For page-based licenses, it also reports the remaining page balance and any potential overconsumption, so you can track license usage without an external tool.

Changed​

• HEVC decoding library (libde265) is dynamically linked
  The libde265 library, which reads HEVC-encoded HEIF images, ships as a separate dynamically linked library. The native library requires the HEIF/HEIC decoding library at load time, even if your application doesn’t use HEIF/HEIC functionality. If Pdftools SDK Shell Tool can’t find the libde265 decoding library, it fails to load. Pdftools SDK Shell Tool includes the required binaries. Action: After updating, verify that your deployment can still decode HEVC-encoded HEIF images.

Fixed​

• Before this update, the optimize-web and optimize-minimal profiles didn’t downsample or recompress bitonal (scanned black-and-white) images, so optimizing a scanned PDF produced a file roughly the same size as the input. With this release, the profiles downsample bitonal images and re-encode them with JBIG2. As a result, scanned documents optimize to substantially smaller files.

Versions earlier than 1.13.0 are no longer available …

24 April 2026

Added​

• ocr command for making PDFs searchable
  The new ocr command applies OCR to a PDF from the command line. It connects to a Pdftools OCR Service instance, recognizes text in scanned images, fixes non-extractable text, and can add accessibility tagging. Example: pdf in.pdf ocr -ocr service -oim updateText out.pdf. For full options and examples, refer to OCR a PDF with the Shell Tool.
• -lgs option for the Licensing Gateway Service endpoint
  If you use a page-credit license key, you can configure the Licensing Gateway Service (LGS) endpoint directly from the command line using -lgs <url>. The URL accepts the form (http|https)://[user[:password]@]host[:port]. When you don’t specify the option, Pdftools SDK Shell Tool uses the default licensing endpoint.
• -d option for dithering control in Fax image conversion
  The Fax conversion profile exposes a dithering option, letting you switch between Halftone (default), None, FloydSteinberg, and Atkinson when rendering PDFs to fax-ready images. For more details, refer to Fax conversion profile.

Fixed​ …

11 March 2026

Changed​

• HEIF/HEIC codec library dynamically linked

  The native library requires the HEIF/HEIC decoding library at load time, even if your application doesn’t use HEIF/HEIC functionality. If the decoding library isn’t found, the native library fails to load. The required binaries are included in the distribution, but ensure your service, container layout, library search paths, and permissions allow the library to be found.

  Action: After updating, verify that your deployment loads correctly even if HEIF/HEIC processing is not used.

• JBIG2 decoding update

  The JBIG2 decoding implementation has been replaced. JBIG2-encoded images render identically, but error messages related to JBIG2 processing may differ from previous versions.

  Action: If you process PDFs with JBIG2-encoded images, consider validating against a representative document set.

• Updated font substitution for missing fonts (including PDF/A)

  When PDFs reference fonts that aren’t embedded and are unavailable on the host, the software substitutes fallback fonts. The updated fallback fonts support a larger glyph set and better fitting to original glyph dimensions. Layout should remain stable, but visual appearance differs from both the original font and previous versions.

  Action: If exact reproduction is required, install the original font in your environment. …

29 October 2025

Added​

• Enhanced logging configuration environment variables:
  • PDFT_LOG_OUTPUT for output control, replacing PDF_TRACE_OUTPUT. The PDF_TRACE_OUTPUT also remains supported for backward compatibility.
  • PDFT_LOG for log level filters. The comma-separated format: *:error,libbase:info, where * sets the default level.

Changed​

• Switched from the zlib to zlib-ng library, significantly improving performance when compressing and decompressing Flate streams by using SIMD instructions.

Fixed​

• Correct the usage text for the render-archive operation as there is no -max option in the general options.
• Corrected conformance retrieval logic in the GetConformance method to properly handle invalid ConversionOptions values.
• Certificate loading on Windows now includes Local Machine store in addition to Current User store, resolving certificate access issues for Internet Information Services (IIS) applications running under service accounts.

16 September 2025

Fixed​

• Resolved an issue using an uninitialized variable that could cause unpredictable behavior during PNG processing.
• Fixed a stack buffer overflow when creating annotation appearances.
• Corrected glyph position problems caused by improper handling of adjustment values.
• Ensured the GTS_PDFX output intent is correctly copied into the output document to maintain PDF/X compliance. The GTS_PDFX defines the standardized printing output intent for PDF/X files.
• Fixed an infinite loop that could occur during optimization for specific malformed PDF files.
• Addressed an access violation related to cross-reference (xref) tables, preventing potential crashes.

23 April 2025

Added​

• Add the support to embedding files during a PDF/A conversion: embedding files can be associated to the converted PDF
• Add fit page option to the import image functionality: all images will be scaled to fit the page size (including enlarging smaller images).
• Improved support for HEIC files.

Fixed​

• Fixed a bug that caused crashes when handling JPEG images with the Pdftools SDK on 32-bit Windows systems.
• Improved handling of faulty PostScript string syntax to ensure correct parsing of ToUnicode maps.
• Previously, document timestamps (ETSI.RFC3161) were not recognized if the PDF lacked an explicit declaration of the correct signature type. This update ensures that timestamps are correctly validated as long as the signature itself is valid and the signed content remains intact.
• Previously, rendering PDFs with the wrong alternate colorspaces could cause the Pdftools SDK to crash. With this update, the rendering engine now falls back to CMYK rendering if the alternate color transform cannot be created, preventing the crash.
• Previously, under certain circumstances, a regression caused the decryption of encrypted PDFs to fail. The issue is fixed with this release.

10 January 2025

Added​

• Add a new method AddAssociatedFile that lets you to embed a file into a PDF. For more information, review the API references: C, Java, .NET, Python.
• The Pdftools SDK Shell Tool now natively supports Microsoft Windows ARM64 processor architecture.

Fixed​

• Add ability to get a license key from a default location when none is provided. The usage help message will display the alternative locations of the license (file or env. variable)
• Corrected encoding of console text output.
• Shell tool version couldn’t be fetched from the executable and properly display in usage help message. …

10 June 2024

Added​

• Support for converting a PDF document and an XML file to a PDF/A invoice in ZUGFeRD or Factur-X format. You can pass an optional -xml <file> parameter to the convert command of the Pdftools SDK Shell Tool to embed the specified XML file and create the invoice.
• You can rotate a page when copying it from one PDF to another. Pass the optional -rot <value> parameter to the merge command to rotate a set of pages by the specified value (90, 180, or 270 degrees) before adding them to the output file.
• Support for digital signature functionality using the Pdftools SDK Shell Tool. You can sign, certify, and timestamp PDF files. You can also add and list signature fields, and check the validity of the digital signatures in a PDF document.

22 September 2023

Added​

• Support for converting images to PDF or PDF/A files

• Support compression and optimization of PDF files for web, archive, or print to minimize the file size.

• Pdftools SDK

  • Version 1.20.1
  • Version 1.20.0
  • Version 1.19.0
  • Version 1.18.0
  • Version 1.17.0
  • Version 1.16.0
  • Version 1.15.0
  • Version 1.14.0
  • Version 1.13.1
  • Version 1.13.0
  • Version 1.12.0
  • Version 1.11.1
  • Version 1.11.0
  • Version 1.10.0
  • Version 1.9.1
  • Version 1.9.0
  • Version 1.8.0
  • Version 1.7.0
  • Version 1.6.0
  • Version 1.5.0
  • Version 1.4.0
  • Version 1.3.0
  • Version 1.2.0
  • Version 1.1.0

• Pdftools SDK Shell Tool

  • Version 1.14.0
  • Version 1.13.0
  • Version 1.12.0
  • Version 1.11.0
  • Version 1.10.0 …