T2 SDE is under continuous development. Instead the development work is done in the revision control system trunk/, with a version as target milestone, for example 6.0, 7.0, ... 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, packages and target configurations build perfectly at any given time.

The packages of the development edition tend to be more up to date than the stable ones (active maintenance of the packages continues as a group effort and the stable packages get maintained as a different effort). Sometimes the development edition will be in research mode adapting the latest kernel/gcc, C library 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 the latest stable tree. The development tree is usually used to rearrange the build script for new features and only be used by developers and only when it approaches the next stable release by normal users.