How to appropriately scale up cantrips players want to cast using spell slots? Like, Ray of Frost with a 9th level slot, etc. Check spell design guidelines in DMG, lists typical damage by spell level. I'd use that.

— Mike Mearls (@mikemearls) July 8, 2017

So RoF would become 15d10 with 9th level slot? Or 60d10 since it’s 4x the damage at 17th (4d10 for cantrip) 15d10 – i'd use listed damage without multiplier

— Mike Mearls (@mikemearls) July 9, 2017