Do you mean like eg Dorian, Phrygian...? You can create these kinds of custom scales by hacking the presets. Here's a Dorian one. You should be able to drop that file into eg the Lead Presets folder; under Windows that's probably:
C:\Users\<username>\AppData\Roaming\Artiphon\Orba\Presets\Lead
If you load a Song from the browser, then load that Dorian preset, you should find that your lead has been tuned to a Dorian scale.
You can't transpose these custom scales however; if you change the tuning they'll revert to the standard type.
It's not ideal but you might find it a helpful workaround until Artiphon provide more scales. The method for creating these custom tuning presets is described at the bottom of this thread:
https://artiphon.freshdesk.com/support/discussions/topics/44001013185/page/4?url_locale=
ohbeegee
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