Two games in a row, I used Renounce Darkness and it gave me upgraded hero powers. According to the wiki, it’s only supposed to give you a basic hero power. It doesn’t happen every time, as I’ve gotten basic hero powers too.
17.2 reorganized the hero powers and upgraded hero powers to be part of the core set:
https://us.forums.blizzard.com/en/hearthstone/t/renounce-darkness-gave-me-an-upgraded-hero-power/33023
17.2 reorganized the hero powers and upgraded hero powers to be part of the core set:
This appears to have had the side effect of making Renounce Darkness able to select them.