A simple question : can I use Dorico to write music in a mode, rather than a diatonic scale ?
Sure, though Dorico doesn’t have any way of enforcing this as you write. However, it’s easy to “snap” any music you write to a particular mode using the feature to map notes to a scale:
And here are the steps for adding accidentals as you input notes.
Thank you both. I thought it would be possible, although I must watch for accidental changes as appropriate.