Open Source Software: Qt Source Code
LimitState products include the Qt framework, which is used under the terms of the GNU Lesser General Public License version 3 (LGPLv3). This page provides the complete corresponding source code for the Qt libraries distributed with our software, as required by that licence.
The archives below contain the unmodified Qt release source as published by The Qt Company, together with build information and the full licence texts. LimitState Ltd has applied no patches or modifications to Qt.
| Qt version | Distribution | Archive | Size | MD5 |
|---|---|---|---|---|
| 5.9.4 | Windows | qt-everywhere-opensource-src-5.9.4.zip | 627 MB | Link |
| 5.9.4 | Mac / Linux | qt-everywhere-opensource-src-5.9.4.tar.xz | 389 MB | Link |
| Product | Release | Qt version |
|---|---|---|
| LimitState:GEO | 3.5a onwards | 5.9.4 |
| LimitState:RING | 3.2c onwards | 5.9.4 |
| LimitState:SLAB | 2.1a onwards | 5.9.4 |
Modifying or replacing Qt
Our products link dynamically to the Qt libraries installed alongside the application executable. You may replace those libraries with your own build of Qt, provided it is interface-compatible with the version listed above.
Licence texts
GNU Lesser General Public License v3 (LGPL-3.0.txt)
GNU General Public License v3 (GPL-3.0.txt)
Other third party components
Mathematical programming solver: © Mosek ApS - Fruebjergvej 3, Box 16 - 2100 Copenhagen O - Denmark
Software kernel (parts): © University of Sheffield - Sheffield - UK
Questions
If you have difficulty obtaining the source code, or need it supplied on physical media, contact us at info@limitstate.com. We will provide it at no more than the cost of the medium and postage.
Last updated: 27th August 2026