In the upgrade planner, the 'upgrade from' selections seem to only show the base solar panels, which means that any later stages can't be upgraded with it, while the 'upgrade to' selection shows every possible quality.
Admittedly only relevant while also using the Advanced Solar mod (https://mods.factorio.com/mod/Advanced-Electric-Revamped-v16), but still. Also seems pretty similar to the recently-solved issue at https://mods.factorio.com/mod/solar-productivity/discussion/67254c91a80c31482dc6e839 so hopefully an easy fix?
