[Q]

I hit the upgrade button, change the design name from "Antares X" to "Antares XI" (or similar), hit the create button. Then the old design is already selected and you hit the make obsolete button.
Yes you have to do this for every design where the new components are used but it is quite fast IMO, at least much faster than in SE V at the moment.
And if you have old designs under construction don't remove them but retrofit them after they are finished, otherwise you loose what already has been constructed.