PDF Tools SDK Updates & Release Notes

Added

• Dithering control for Fax image conversion The Fax conversion profile exposes a dithering option, letting you switch between dithering modes when rendering PDFs to fax-ready images. For more details, refer to Fax conversion profile.

Fixed

• Before this update, PDF/A conversion incorrectly reported a device-color-space error on documents containing nested form XObjects. As a consequence, valid documents couldn’t be converted to PDF/A. With this release, the converter resolves color spaces correctly. As a result, these documents convert to PDF/A as expected.
• Before this release, optimizing PDFs with certain internal structures caused the optimizer to perform many redundant object comparisons. As a consequence, optimization appeared to hang and didn’t complete on the affected documents. With this release, the optimizer avoids the redundant comparisons. As a result, optimization finishes in the expected time on the affected documents.
• Before this update, validating a malformed PDF containing nested object streams caused unbounded recursion. As a consequence, the process crashed with a stack overflow on the affected documents. With this release, the validator detects the cycle and rejects the document with a clean validation error. As a result, malformed input can no longer crash the validator.

Added

• OCR pre-processing for PDF workflows. Apply OCR to scanned PDFs and images through Pdftools SDK workflows (PDF to PDF/A conversion, conformance validation, digital signing). Connect to an OCR service endpoint to perform recognition without changing application logic. For more details, refer to OCR.

Fixed

• Before this update, certain conversion events, such as XMP metadata information loss, weren’t tracked through the Pdftools SDK error reporting during PDF/A conversion. As a consequence, applications using the SDK didn’t receive these error flags, and conversion issues could go unreported. With this release, conversion event tracking is consistent across all usage paths, and XMP metadata-related errors are properly reported.
• Before this update, generated API interface event handlers didn’t release resources correctly. As a consequence, applications experienced increasing memory consumption over time. With this release, event handlers release resources as expected.

Added

• ForbidImplicitUpgrade option on ConversionOptions to prevent automatic PDF/A conformance level upgrades during conversion.

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.

• ZapfDingbats font delivery change

  ZapfDingbats is no longer shipped. The fallback font URW++ D050000L.ttf is used instead, but it doesn’t provide full coverage and may differ slightly in appearance.

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

• Refreshed internal mapping tables

  Character mapping tables used for Unicode and glyph mapping have been updated. Changes are primarily additive (new code points) with occasional correctness fixes.

• Java: native library loaded automatically

  Before this release, Java applications had to explicitly locate and load the Pdftools SDK native binary using System.load() or System.loadLibrary() before calling any SDK function. With this release, the native binary is loaded automatically at runtime.

  The Maven dependency has also been simplified: the platform-specific native artifact classifier is no longer needed.

  Action:
  Remove any System.load() or System.loadLibrary() calls for the Pdftools SDK native library from your code. In your code pom.xml , replace the two-dependency block (main JAR + native artifact) with a single dependency on pdftools-sdk . Refer to the Java getting started guide for the updated configuration.

• Upgraded libxml2 from version 2.10.3 to 2.15.0. Error messages related to XML processing may differ from previous versions.

Fixed

• Debug-level log messages are written to the file output sink when file logging is configured via PDF_TRACE_OUTPUT or PDFT_LOG_OUTPUT.
• Fixed a crash when repairing PDFs with XMP metadata dates missing timezone information.
• PDF/A conversion no longer fails when the document contains a /Tabs entry written as a string instead of a name object.
• PDF/A conversion no longer fails when the document contains a CIDFont dictionary without a /Type entry.
• The remove-PieceInfo option (eStripPieceInfo ) also removes PieceInfo dictionaries from XObject resources.
• Before this update, on Linux, PDF dates were computed using the UTC offset of the current time instead of the UTC offset applicable to the date being processed. As a consequence, PDF dates could be off by one hour when the document’s date and the current time fell in different daylight saving time (DST) periods. With this release, the UTC offset is correctly derived from the date being processed.
• Before this update, the JBIG2 decoder placed no limit on memory allocations, which could cause excessive memory consumption when processing PDFs with malformed or unusually large JBIG2-encoded images. With this release, JBIG2 memory allocation is capped at 2 GB.
• Before this update, calling Extractor.ExtractText() using the C# binding on Linux produced incorrect output. As a consequence, non-ASCII UTF-8 characters were silently dropped from the extracted text. With this release, text extraction produces correct UTF-8 output on Linux.

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

• 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.
• Widget annotation appearance generation now correctly checks for rich text value (RV) entry instead of rich text style (DS) entry when determining whether to create appearance streams.

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.

Added

• Added IsFullRevisionCovered flag to signature validation results to detect partial ByteRanges.

Changed

• Removed library load/unload messages from Python bindings.

Fixed

• Font name decoding for Type0 fonts on Linux and macOS to preserve Unicode characters.
• Malformed import in native_base.py that caused errors in Python bindings.
• Fixed error reporting for non-UTF8 colorant name on Linux and macOS.
• Font name decoding on Linux and macOS to align behavior with Windows.
• Fixed unexpected termination when processing image dictionaries with an empty /Filter array.
• Removed stray null terminators from strings returned by the Python interface.

Added

• With this release, we are launching a new Python Jupyter notebooks repository demonstrating the core functionality of the Pdftools SDK, including step-by-step examples for key features and use cases.

Fixed

• 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.
• Prior to this update, a crash occurred when IIS processes terminated, causing the Pdftools SDK DLL to unload without properly releasing its resources. With this release, the issue has been resolved, allowing the DLL to safely unload even when shutdown hooks fail to execute as expected.
• 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.

Added

• The Pdftools SDK now natively supports Microsoft Windows ARM64 processor architecture.
• During PDF/A conversion, you can now add embed associated files using the AddAssociatedFile method.
• Test whether any update leading to a specific revision does not contain a digital signature using the new HasNonSigningUpdates property.
• Suppress rendering of text when converting a PDF to an image using the new RenderText property.
• With this update, you can force an image to fill the page (respecting the image’s aspect ratio) using the ForceFit property.
• With this update, the Pdftools SDK introduces a new Pythonic, object-oriented interface with structured classes, native Python types for data handling, and enhanced error management through exceptions. For more details on how to try the new Pythonic interface, review Python getting started guide .

Fixed

• Missing firstChar or lastChar entries in damaged font dictionaries are restored when enough information is available.
• Fixed issue for PDFs with signed signature fields without any appearance.
• There was an issue when the SDK tried to get resources by HTTPS in the visual appearance of JSON or XML configuration files. The issue was fixed with this update.

Added

• The Pdftools SDK now lets you adjust the image quality using the ImageQuality property when converting a PDF file to PDF/A. This setting is used when images must be recompressed during the conversion process.
• You can now use pip package manager to install the Pdftools SDK. Use pip install https://pdftools-public-downloads-production.s3.eu-west-1.amazonaws.com/productkits/PDFSDK/latest/pdftools_sdk-latest.tar.gz to install the Python version of the Pdftools SDK from our servers.

Fixed

• Corrected an issue where Unicode characters were sometimes converted incorrectly when using the Python version of the Pdftools SDK.
• Fixed a bug where some ZUGFeRD v3 invoice XML files were not correctly recognized by the AddInvoiceXml method when creating a ZUGFeRD invoice.

Added

• You can now create a fully compliant ZUGFeRD or Factur-X invoice using the Pdftools SDK. To do this you add the invoice XML file before calling the Convert method.
• It is now possible to rotate a page when merging pages of PDF documents using the Assemble method.
• Instead of using the default Font directories, you can now also add a custom font directory using the AddFontDirectory method.

Fixed

• Previously, a default value was always used for the PDF Producer value. With this update, the issue was fixed, and the PDF Producer value is now set correctly using the producerSuffix parameter of the Initialize(licenseKey, producerSuffix) method.
• The validation of a digital signature’s Appearance has been improved, to prevent inconsistent boundary values.