QGroundControl (QGC) is dual-licensed as Apache 2.0 and GPLv3. All contributions have to be made under both licenses (see [CONTRIBUTING](CONTRIBUTING.md)).
## Apache 2.0 License
The [Apache 2.0](http://www.apache.org/licenses/LICENSE-2.0) License is a permissive license which allows QGC to be built and used in any environment, including proprietary applications. It allows QGC to be built for mobile app stores. When building with Apache 2.0 a commercial Qt license is required.
## GPL v3 License
The [GPL v3 License](http://www.gnu.org/licenses/gpl-3.0.en.html) is a strong copyleft license. When building QGC under this license the open source version of Qt can be used. Our licensing grants the permission to use a later version of the license, however, contributions have to be made under 3.0.
## Contact
If you have questions regarding the licensing, please contact the maintainer Lorenz Meier, [lm@groundcontrol.org].
@@ -33,11 +34,12 @@ QGroundControl builds are supported for OSX, Linux, Windows, iOS and Android. QG
* Windows: Vista or higher, 32 bit, [Visual Studio 2013 compiler](http://www.visualstudio.com/downloads/download-visual-studio-vs#d-express-windows-desktop)
* iOS: 8.0 and higher
* Android: Jelly Bean (4.1) and higher
* Qt version: 5.5.1 (or higher)
* Qt version: 5.5.1 ONLY
###### Install QT
You need to install Qt like this instead of using packages from say a Linux distribution because QGroundControl needs access to private Qt headers.
* Download the [Qt installer](http://www.qt.io/download-open-source)
* Make sure to install Qt 5.5 version NOT 5.6
* Ubuntu: Set the downloaded file to executable using:`chmod +x`. Install to default location for use with ./qgroundcontrol-start.sh. If you install Qt to a non-default location you will need to modify qgroundcontrol-start.sh in order to run downloaded builds.
* Windows: Default installer not quite correct, use [this](http://download.qt.io/official_releases/qt/5.5/5.5.1/qt-opensource-windows-x86-msvc2013-5.5.1.exe) instead