iTextSharp is a .NET port of the iText PDF library. Version 4.1.6.0 was the final release published under the LGPL 2.1 / MPL 1.1 dual license. All subsequent releases (5.x and later, now rebranded as iText 7) switched to the AGPL, which requires that any web application serving output produced by the library either be open-source or purchase a commercial license.
If your project cannot comply with the AGPL and a commercial license is not an option, 4.1.6.0 remains a legitimate choice: the LGPL permits use and redistribution in proprietary applications with no source-disclosure obligation.
License
This DLL is redistributed under the terms of the GNU Lesser General Public License v2.1 and the Mozilla Public License 1.1. The LGPL permits use of this library in proprietary applications and redistribution of the unmodified binary, provided the following conditions are met:
- You must make clear that iTextSharp is used and that it is licensed under the LGPL/MPL.
- If you distribute a modified version of the DLL itself, you must release the source of your modifications under the LGPL.
- You must allow recipients to obtain the original source code. The 4.x source is available on SourceForge: sourceforge.net/projects/itextsharp.
Compatibility Note
iTextSharp 4.1.6.0 targets .NET Framework. It can be referenced in .NET 5+ projects but some
APIs that rely on System.Drawing or System.Web may require additional
compatibility packages. For new projects on modern .NET consider
PdfPig or
QuestPDF as
LGPL/MIT-licensed alternatives with native .NET 8 support.
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