[aculver]

I've got one you can add: iPad applications don't have to support all four orientations. However, whichever orientation you do support (in our instance, portrait) you must support the top-up and bottom-up variations unless some special circumstance warrants only supporting one or the other. Just had a submission rejected earlier this week for this reason. FYI, here is the response we received from Apple:

10.1

We found that your app does not comply with the Apple iOS Human Interface Guidelines, as required by the App Store Review Guidelines.

Specifically, we noticed your app only supported the top-up variant of the portrait orientation, but not the bottom-up variant.

While supporting both variants of both orientations, each with unique launch images, provides the best user experience and is recommended, we understand there are certain applications that must run in the portrait orientation only. In this case, it would be appropriate to support both variants of that orientation in your application, e.g., Home button up and down.

Addressing this issue typically requires only a simple and straightforward code modification. However, if you require assistance, the Apple Developer Support Team is available to provide code-level assistance.

For more information, please review the Aim to Support All Orientations section of the iOS Human Interface Guidelines.

[Ein2015]

I often have my iPad with the home button on top while on the stand. Easier for charging...

(Just in case anybody wonders why they'd want both orientations...)

[pmjordan]

Another reason is that the speaker is on the side with the home button. Having that edge face downwards when sitting down e.g. in bed muffles the sound. Not sure if this still applies to iPad 2, but it certainly does for the original.

[bryanlarsen]

I find that I'm often using the iPad "upside down". It wasn't on purpose, but there are very few reasons to care which way you're picking it up. It would be jarring to discover an app that cared.

[baddox]

Is there not an easy way to just say "turn my app upside down when the user flips the device"? For most apps (i.e. ones that don't use the accelerometer, etc.) this should be trivial, and shouldn't require any real effort from the app developer.

Also, I agree with Apple that both orientations should be supported. Depending on how you're holding or docking the device, and where it's convenient for the headphone jack to protrude, it's quite conceivable for users to want to use both orientations.

[coob]

Yes this is trivial.

[kevinh]

Assuming you programmed your app correctly, you only need to override the function shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation to return true for the supported orientations. If you use portrait orientation, you can get portrait upsidedown for "free", as it rotates the view for you. It's the same with LandscapeLeft and LandscapeRight. The only complications come when you want to support both portrait and landscape orientations, which isn't required anyway.

[xsmasher]

It's trivial to support two orientations, but Apple had (has?) a guideline that said you must support all four orientations. That's not necessarily trivial, although Apple's UI kit has features to help you there too.

[TheFuture]

Thanks for letting us know. I actually have an iPad app currently in the store (approved in October) that only supports top-up portrait. I guess it really depends how picky the reviewer wants to be. I will make sure I fix it before my next update.

[stefanbutlin]

Nice clarification. Have updated the list.