Yesterday, after 15 years a new official release of GROMOS (in C++) has seen light of the day. All informations are available on this website: www.gromos.net
GROMOS11 relies on 30 years of scientific research for biomolecular simulation (soft matter). Primarily, in contrast to other packages it has to suit the needs of the scientific community.
The models (force-fields) have been further developed over decades and are highly specialised for proteins, sugars and lipids. In contrast to simpler models, they are fitted on experimental thermodynamical data of liquids and not on structures in vacuum.
We from xirrus have developed with GROMOS96, respectively worked on its models earlier and own a life long license.