Oh really? That was my initial assumption (that it was an iOS 8 API that devs would have to update for) but I couldn't even see it in any stock apps. Then I found a pic online of an earlier iOS 8 beta
showing the App Store offering all three options, but on my iPhone 5 running 8.0.2 I only see two for the App Store. That could just be an intentional change Apple made between the early beta to GM, but the impression I got from speaking to others was that it might be a bug.
If you could list some apps that have all three options that'd be great - I currently don't have any and I'm weirdly excited to see it in action

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Ah yes, I remember the other thing making me think it might be a bug... Reminders only allows Never or While using the App. Now I know location based Reminders can be sketchy at their best, but I had location reminders not working, and I presumed because I couldn't set 'Always'.
Does anyone know if this is a bug / what the Reminder options are in iOS 8.1? Even if Reminders can 'break the rules' and ignore this setting because it's a stock App, it seems wrong to be so unclear about it on this screen!