Any version before 1.0 is considered the old boson. Although I will accept bug fixes for it (branched from old_boson), I will not accept any new features. Since the new boson supports almost all of boson's origin functionality via plugins, there is little reason to hang onto this version.
To enjoy the same experience you've had with the old boson, you'll need to also install boson-more and create a ~/.bosonrc:
$ gem install boson boson-more $ echo "require 'boson/more'" > ~/.bosonrc
Your old boson config and libraries should just work. Please file issues with your libraries or any upgrade issues at boson-more.
If you've written custom plugins for the old Boson, you most likely have to upgrade to the new API.