Seems to be whatever the latest from the app store is.

I can change amounts if I tap the LNaddress in someone's profile from amethyst, but not for zapping a specific post. And I still can't figure out how to zap you from amethyst at all. Your address isn't showing on your profile for me. Idk, I'm not running the latest git version for either, so maybe it'll be fixed as the newer releases get pushed to the app stores