A beta version implementing the new version handling has been uploaded: http://code.dlang.org/download
The idea is that it should work for the same dependency graphs as before, but issue warnings whenever branch based dependencies are encountered. However, there have been some deep changes that probably still broke some stuff. Also, performance is sometimes lacking and the error message for unresolvable dependency graphs is bad. But I think everything is now complete enough to start looking for regressions and to start stabilizing everything.
In addition to that, I've started to change the dependencies of the my own packages to reference tagged versions, so that may also require some updates to resolve conflicts.