Release management
Learn about versioning of the Pdftools products and their supported releases.
Versioning
The Pdftools products use semantic versioning. The version is marked as MAJOR.MINOR.PATCH. For example, a product with version 5.1.1 indicates a major version 5, a minor version 1, and a patch version 1.
Tables in the following sections sometimes intentionally exclude the patch part (third number) of the version. LTS releases receive only patches, so the last number changes with each patch.
Feature releases
Feature releases receive regular updates with new features and bug fixes. As a result, they deliver stability improvements and product advancements. Patches are provided until the next feature release. Previous feature releases aren’t supported.
The following products receive feature releases:
- Pdftools SDK
- Pdftools SDK Shell Tool
- Toolbox add-on
- Conversion Service
- PDF Viewer SDK (version 5.x)
- Pdftools OCR Service
Long-term support (LTS) releases
Long-term support (LTS) releases receive regular patches with bug fixes. LTS releases involve extended test and integration processes that focus on long-term stability.
Each LTS release is supported until its end-of-life (EOL) date, after which the release no longer receives patches.
Stable 3-Heights® products
The following 3-Heights® products are actively maintained and receive security fixes, patches, and smaller improvements. No successor is planned for these products, and no EOL date is announced.
The following table lists each product and its current LTS version:
| Product | LTS version | Supported until |
|---|---|---|
| 3-Heights® PDF Printer | 6.27 | No EOL date |
| 3-Heights® PDF Producer | 6.27 | No EOL date |
| 3-Heights® PDF to Image Converter | 6.27 | No EOL date |
| 3-Heights® Scan to PDF Server | 6.27 | No EOL date |
Legacy 3-Heights® LTS releases
The following 3-Heights® products are actively maintained but are being phased out. They are succeeded by the Pdftools SDK. An EOL date is announced once the successor is feature complete.
The following table lists each product and its current LTS version:
| Product | LTS version | Supported until |
|---|---|---|
| 3-Heights® PDF Security | 6.27 | No EOL date |
| 3-Heights® PDF to PDF/A Converter | 6.27 | No EOL date |
| 3-Heights® PDF Optimizer | 6.27 | No EOL date |
| 3-Heights® PDF Extract | 6.27 | No EOL date |
| 3-Heights® PDF OCR | 6.27 | No EOL date |
Other supported LTS releases
LTS releases for the following products receive patches until the dates indicated in the following tables.
3-Heights® products
The following 3-Heights® products receive LTS patches until the end of 2027. The Pdftools SDK succeeds most of them, the Pdftools OCR Service succeeds the 3-Heights® OCR Service, and the Conversion Service succeeds the 3-Heights® Document Converter. To move to the Conversion Service, see the migration guide.
| Product | LTS version | Supported until |
|---|---|---|
| 3-Heights® PDF Validator | 6.27 | End of 2027 |
| 3-Heights® PDF Merge Split | 6.27 | End of 2027 |
| 3-Heights® PDF Analysis & Repair | 6.27 | End of 2027 |
| 3-Heights® Image to PDF Converter | 6.27 | End of 2027 |
| 3-Heights® OCR Service | 6.27 | End of 2027 |
| 3-Heights® Document Converter | 6.27 | End of 2027 |
4-Heights® products
The 4-Heights® PDF Toolbox SDK is succeeded by the Toolbox add-on. The Toolbox add-on is fully backwards compatible with the 4-Heights® PDF Toolbox SDK, so no code changes are needed beyond updating import and usage paths. See the migration guide for details.
The following table lists the supported 4-Heights® LTS release:
| Product | LTS version | Supported until |
|---|---|---|
| 4-Heights® PDF Toolbox SDK | 4.4 | End of 2027 |
PDF Viewer SDK
PDF Viewer SDK version 4.x is in long-term support. Current development happens in version 5.x, which receives feature releases.
The following table lists the supported PDF Viewer SDK LTS release:
| Product | LTS version | Supported until |
|---|---|---|
| PDF Viewer SDK | 4.3 | May 2027 |
Conversion Service
Conversion Service versions 4.x and 5.x are in long-term support. Current development happens in version 6.x, which receives feature releases.
The following table lists each supported Conversion Service LTS release:
| Product | LTS version | Supported until |
|---|---|---|
| Conversion Service | 4.8 | End of 2025 |
| Conversion Service | 5.7 | End of 2026 |
Version availability
The latest versions of all Pdftools products are available. For most deployments, updates require no extra work, but review the relevant release notes for any product-specific changes. Update to benefit from the latest features, stability improvements, and security updates.
Earlier versions are deprecated. Pdftools removed them from the customer portal and delisted them from the public package repositories.
By June 20, 2027, update to the following or later versions:
| Product | Update to at least | Released |
|---|---|---|
| Pdftools SDK | 1.18.0+ | 26 May 2026 |
| Pdftools SDK Shell Tool | 1.13.0+ | 26 May 2026 |
| Toolbox add-on | 1.13.0+ | 26 May 2026 |
| Conversion Service | 6.12.1+ | 25 June 2026 |
| Pdftools OCR Service | 1.1.4+ | 19 June 2026 |
| PDF Viewer SDK | 4.3.7+ (4.x), 5.16.0+ (5.x) | 26 May 2026 |
| 3-Heights® products | 6.27.17+ | 18 June 2026 |
After updating
These changes are internal to the PDF engine shared across Pdftools products. Whether you need to take action depends on how you deploy the product:
- No action needed for Conversion Service, Pdftools OCR Service, and PDF Viewer SDK, and for any product installed with an
.msiinstaller. These ship the required libraries and load them automatically. - One extra step for Pdftools SDK, Pdftools SDK Shell Tool, Toolbox add-on, and the 3-Heights® API and Shell products, which you deploy as native libraries yourself, typically from a
.zippackage. Copy the HEIF/HEIC decoder libraries,libheifandlibde265, into the same location as the Pdftools library file (.dll,.so, or.dylib). The Pdftools library loads these decoders at startup, even if your application doesn’t process HEIF/HEIC images, and fails to load if they’re missing.
The following rendering and text-output changes also come from the shared PDF engine:
- JBIG2 images: A new decoder produces identical rendering; only the wording of some error messages differs.
- Font substitution: When a required font isn’t embedded or installed, the engine substitutes a different fallback font than in earlier versions. Layout doesn’t change, but substituted glyphs may look different. To reproduce the exact appearance, install the required fonts where the product runs.
- ZapfDingbats: The products no longer bundle ZapfDingbats and fall back to the URW++
D050000Lfont. To reproduce the exact appearance, install ZapfDingbats where the product runs. - CJK text: Refreshed character mappings for Chinese, Japanese, and Korean improve text extraction, copy-and-paste, and search. The extracted text may differ at the byte level from earlier versions.
The 3-Heights® product packages include the release notes as PDF manuals.
Discontinued products
The following products are no longer supported. Where applicable, the successor product is indicated after the arrow (→).
- Classic product generation:
- PDF Prep Tool Suite → Pdftools SDK
- PDF Command Line Suite → Pdftools SDK Shell Tool
- PDF Form Filling and Flattening Tool → Toolbox add-on and Pdftools SDK, depending on the feature
- PDF Batch Stamp Tool → Toolbox add-on
- The following 3-Heights® generation products:
- 3-Heights® Signature Creation and Verification Service
- 3-Heights® PDF to EMF Converter
- 3-Heights® PDF Document Assembler
- 3-Heights® PDF Creator API
- 3-Heights® PDF Toolbox SDK → Toolbox add-on