The Mac version allows conversation view to be disabled, but the iOS version does not have this essential setting. Please add. Thank you!
Added since 1.12: Prefs > Behaviors > Conversations > Off
I've had to turn off conversation view, as new e-mails would not necessarily be brought to my attention, but just silently put in with the rest of a conversation, without the conversation bubbling to the top and the unread count increasing.