Tobias Geerinckx-Rice writes: >> can I express "any version of ffmpeg"? > > No, this would go against the goals of Guix: packages can't depend on properties of the environment they'll end up in (if any). What’s the right way to deal with this, then? I need ffmpeg at as propagated-input, but I do not want to create a conflict with a manifest that just defines "ffmpeg". Best wishes, Arne -- Unpolitisch sein heißt politisch sein, ohne es zu merken. draketo.de