Forte 4.1.7 and later uses the open source version of Qt 5.5 under the LGPLv 2.1 license (with the Digia Qt LGPL Exception version 1.1.).

No source code customization or enhancements were made to the Qt source.

Forte 4 links against DLLs (dynamic link libraries) containing the Qt code and is compatible with 32 bit and 64 bit Windows on Intel x86 32 and 64 bit architecture processors.  Forte does not run on ARM or other embedded devices.

Per the licensing requirement that a user be able to re-link Forte 4 against a modified Qt library, Forte links dynamically to the DLL versions of the libraries, so relinking is possible by replacing the DLL files in the application install directory.  The replacement DLLs must adhere to the same DLL entry points and function prototypes as well as the same processor and OS architecture as the originals.  This is in service to requirement LPGL2.1 section 6b.

The Qt LGPL license page is here: and

The LGPLv3 License is available here:

The LGPLv2.1 License is available here:

The Qt LGPLv2.1 exception is here:

Per license requirements, the Qt source used is available upon request.  As stated above it is unmodified from the official distribution.

This page was last updated on October 1, 2015.