When is really up to Kovid. I know he asked me to tell him when it is in a state for migrating over. The only thing that could be considered outstanding with it is supporting multiple selections to allow a user to upgrade all of their plugins at once. I've expressed my opinions on that a few times in this thread - basically I have no plans at this point to support it unless Kovid says it must be added.
So he is welcome to take the plugin code at any point now to shape it and integrate it with Calibre however he sees fit. I would offer to do it for him but I think it would take longer for me to remotely read his mind than for him to just do it
