# DD4hep 1.8 Released and New License

We are happy to announce a new stable feature release of DD4hep version 1.8 with a total of 105 commits added to the repository since version 1.7. The release tarball can be downloaded from the repository:

https://github.com/AIDASoft/DD4hep/releases/tag/v01-08

This is the first release of DD4hep distributed under the GNU Lesser General Public License v3.0, which was agreed to be the new DD4hep license.

This release has seen some major improvements in different areas, an overview of the most important changes and new features is provided in the following:

• Changes to units:
• DD4hep.py was replaced by dd4hep.py.
• DDG4/SystemOfUnits.py was moved to DDG4/g4units.py.
• SystemOfUnits.py is deprecation and has a warning.
• Updates to the DD4hep manual.
• The Detector object has a state Detector::state() to indicate is the geometry is loaded.
• production cuts may be specified in the compact notation.
• It is possible to define volumes in a parallel world such as e.g. a tracking region. In principle any volume hierarchy may be attached to the parallel world. None of these volumes participate in the tracking as long as the “connected” attribute is set to false.
• World volumes can now be other shapes then boxes.
• Support out-of-source builds of DD4hep examples.
• Support for to save the hit class to ROOT.