T2 is under continuous development, with the development work beeing done in the version control system - currently Subversion. With a version as target milestone, for example 7.0, 8.0, ... When most development goals are archived, this trunk is branched and this version prepared for the release. In parallel development continuous in the trunk with the next milestone version, 8.0 in this case. So each version milestone has a release series in the end of the development cycle. Though the development version from the trunk usually work well enough to download and build a common Linux system, there is no guarantee that all architectures, C libraries, packages and target configurations build perfectly at any given time.

The packages of the development trunk tend to be more up to date than the stable ones, as the branches are usually maintained with API and ABI compatibility in mind and mostly include security and compile fixes only. Sometimes the development edition will be in research mode adapting the latest kernel, C library, compiler or CPU architecture combination or rearranging the build scripts for new features, concepts and cleanups.

If you are a normal user or administrator of production machines you should choose to use the latest stable branch. The development tree is usually used by developers, while users and administrators often only try the trunk when it approaches the next stable release.