Christophe wrote You don't want numbered versions for the parts you don't control. There you want patches to be possible. Dependent projects always need to be referred to by symbolic name. Dependent project are volatile information. https://www.cs.utexas.edu/users/EWD/ewd07xx/EWD719.PDF In Moose, there are at any time a few sub projects that are very active and are very likely to break very soon after (or even at) release. At the moment, that could be PetitParser and Roassal2. As we'll move to Pharo4 straight after this release, the development version is going to be fragile for a while. If we want to be able to patch active projects, we need symbolic versions to make sure that patch versions don't need to propagate to the configurations using them. Stephan