Upgrading from APDFL 18 to APDFL 21: What to Know Before You Start
Moving from Adobe PDF Library (APDFL) 18 to APDFL 21 is often a smaller project than teams expect. For most applications, the work is updating build references, packages, and deployment files, not rewriting code. Applications on recent v18 releases can generally keep their existing APDFL API calls.
This post explains why teams are making the move, what the upgrade involves, and how to find the migration guide that fits your application.
Why Consider APDFL 21?
APDFL 21 is built on Adobe's v21 core and brings improvements to PDF processing, rendering, fonts, and document conversion. It also adds new capabilities:
- WebToPDF for converting web content to PDF
- Vietnamese OCR for text recognition
- Brotli compression when saving PDFs
Recent 21.x releases continue to add features, including PDF/X-4p and PDF/X-5pg conversion for print production workflows.
Availability depends on the release, interface, and platform. Brotli-compressed files also require compatible PDF readers. For the full list, see the APDFL 21 release notes.
What the Upgrade Involves
The upgrade is mostly about keeping your dependencies consistent. You update the APDFL packages or libraries your application references, replace the supporting files that ship with them, and rebuild. Scripts and installers that mention v18 file names or directories need the same attention.
What that looks like in practice depends on your application's interface and runtime. A .NET application has different steps from a Java or Adobe C/C++ application, and each has its own walk-through.
Choose Your Migration Guide
Pick the guide that matches your interface. Each one is a step-by-step walk-through in the Datalogics Knowledge Base.
| Interface | Main changes | Guide |
|---|---|---|
| Adobe C/C++ | Update library names and SDK paths, replace supporting files, and rebuild | Upgrading Adobe C/C++ Applications from APDFL 18 to APDFL 21 |
| .NET | Retarget to .NET 10, then update NuGet packages and native dependencies | Upgrading .NET and .NET Framework Applications from APDFL 18 to APDFL 21 |
| .NET Framework | Stay on .NET Framework 4.7.1 or later, update NuGet packages, and review assembly binding settings | Upgrading .NET and .NET Framework Applications from APDFL 18 to APDFL 21 |
| Java | Plan for JDK 17 or later and update the API, JNI, and resources artifacts together | Upgrading Java Applications from APDFL 18 to APDFL 21 |
Is Modern C++ Required?
No. The existing C++ interface, now called Adobe C/C++, remains supported in APDFL 21, so you can upgrade first and evaluate Modern C++ later.
The Modern C++ SDK is a different kind of project. It offers a C++17 interface with automatic resource management, C++ exceptions, and strongly typed flags, and it runs on the same APDFL runtime. Adopting it is a source-code port to a new API, not a version bump. It also has its own requirements, including a supported 64-bit platform, and does not support 32-bit applications or AIX.
If you want to look at it, start with Migrating from Adobe C/C++ to the APDFL Modern C++ SDK. The Knowledge Base article What is the Modern C++ SDK? gives the background.
Plan the Upgrade in Four Steps
Whichever interface you use, the same four steps apply.
- Check your environment. Confirm the platform, architecture, runtime, and licensing support for the distribution you plan to use. Not every interface supports the same platforms.
- Update dependencies together. Keep API libraries, native binaries, plug-ins, and resources compatible with each other, and review any scripts that reference v18 file names or directories.
- Confirm licensing. Keep the right License-Managed or non-License-Managed distribution, and check license file or server compatibility where it applies.
- Build and verify. Run representative documents through the rebuilt application. Rendering, font matching, and color conversion results can differ with the newer core, so compare output before you ship.
Where to Start
If you are not sure which path applies to your application, begin with Upgrading from APDFL 18 to APDFL 21: Where to Start. It is a two-minute overview that points you to the right guide.
If you get stuck, help is available. Contact Datalogics Tech Support, or ask Scout, our AI assistant, for quick answers in any language. Scout also gives you access to our MCP server, which connects APDFL with your favorite AI tools for faster coding.
Ready to plan your upgrade? Contact the Datalogics team to talk through your application, or download a free trial of Adobe PDF Library 21 to try it on your own documents.