Qt is continuing it progress towards becoming the primary development option for third-party applications on Symbian, with the release of Qt 4.6.1. While a minor release, it brings a big step forward by delivery on the binary compatibility promise made to Symbian developers.

Qt 4.6 was the first release where support for Symbian was incorporated into the main Qt code line. However, it arrived with one significant drawback, a lack of binary compatibility with Qt for other environments. This meant that code created in 4.6 for Symbian would not necessarily execute on other supported platforms and that any code specifically designed for Symbian would need to be recompiled when binary compatibility was achieved.

This situation was certainly a disincentive to developers wanting to seriously look at Qt for applications targeting Symbian. Given Qt will used for the UI framework in Symbian^4, many developers are keen to make the transition sooner rather than later.

So should it be all systems go with Qt 4.6.1? Well it could be, but that probably depends on how comfortable developers are with Symbian C++. Qt has always been a cross-platform framework, but developers may have to revert to Symbian C++ to create the device integration many mobile applications need. This is where the next batch of improvements to Qt will focus, according to the Qt roadmap, by delivering a range of APIs for accessing key information, such as a user’s calendar and location information thought Qt APIs on all supported platforms.

So development is becoming more practical, but what about distribution? The big issue for practical distribution is how to ensure a device, onto which a user installs an application using the Qt framework, has the necessary components to run the application. The Qt framework can be included with applications in their installation file, but the installable framework is upwards of 8 Mb in size. This makes including the framework with a 10k utility application is not practical for widespread distribution. This is a significant hurdle that will need to be overcome before Qt becomes a practical option for the majority of developers.

With the annual announcement fest of WMC taking place soon, it’s probably worth keeping an eye on Qt.

The release includes many bug fixes, both in Qt and Qt Creator, updates to the Qt Visual Studio Add-in and Qt Eclipse Integration, a beta of Maemo 5 support, and an updated build of the Qt SDK.

All Qt releases are available for download from http://qt.nokia.com/downloads.