Comment by jck86

For replaygain purposes simply ignore the spec and use RG 2.0 tags? That works with Opus too and hardly any players support Opus R128 gain anyway. For very low spec devices Vorbis would do a bit better though. For legacy devices legacy codecs can be a better fit indeed.

But would you really store new material encoded in Vorbis just to be able to play it on an old device? Vorbis can sound fine, even at lower bitrates like 128k or 96k, but Opus would sound much better. So perhaps then use Vorbis at higher bitrates like +192k? I prefer Vorbis to Aac but at that bitrate minor intricacies of the container format become more important than the codec because audio quality wise they are near indistinguishable.