Your app:

• Never crashes
• Has no memory leaks
• Works on all iOS devices with different (minimum and maximum!) OS versions and resolutions
• Remains responsive after long/excessive use
• Securely stores sensitive information (Keychain)
• Works with different region and language settings
• Does not make use of any private APIs in the SDK
• Does not make use of any undocumented features in the SDK
• Does not refer to hardware capabilities that don't exist on the user's device
• Warns the user when there is no network connectivity, if it needs a connection
• Handles orientation appropriately
• Does not use any unapproved hardware accessories
• Does not contain a scripting interpreter, plugin, or other runtime that can execute downloaded content
• Does not use continuous vibration
• Uses the relevant keyboard for an input field (e.g., numbers for a phone number field)
• Deselects rows in table views after their selection causes another view to be displayed
• Restricts video streaming or other big downloads to WiFi connections only
• Makes clear to the user when private data will be sent to a server and provides an opt-out
• Does not make covert or non-obvious use of the camera or microphone
• Uses Core Location (GPS) for a real user benefit, not just advertising or tracking (if applicable)
• Does not make excessive use of iCloud storage
• Only stores user-created content in iCloud
• Stores temporary files in /tmp and deletes these on exit
• Uses the "do not back up" attribute for files that need to persist but should not be saved to iCloud

Version compatibility

Make sure that the new release is installed over the old version in a correct way:

• Install the application from the App Store
• Upload a new build to the iTunesconnect
• Enable internal and/or external testing for the new build
• Install the new version from TestFlight over the old version from the App Store
• Check that the user doesn't lose any of their information in the application after the update

Check that the data from NSUserDefaults is read in a correct way:

• App doesn't crash trying to read non-existing keys
• You haven't changed keys in the initWithCoder: and encodeWithCoder: methods (your current app should be able to read data saved by an old version of the application)
  

iOS SDK API updates:

• Check that geolocation is working (iOS8 SDK)
• Check that local notifications are working (iOS8 SDK)
• Check that push notifications are working

Logging

• Remove or disable the NSLog() and print() calls, at least like this: #define NSLog(...)
  

Conforms to Apple's Human Interface Guidelines

• The app looks well-designed and high quality
• Native button icons are consistent with their native actions
• Activity spinners should not spin indefinitely
• Buttons trigger on touch-up inside an event
• Screen layout can handle the double-height status bar (e.g., during a phone call)
• Landscape mode, if supported, looks well-designed (i.e., is not accidental and bad)

You can find more information about this topic here.

iPad-specific

• Your app should work in all four orientations. If it is only portrait or landscape, it has to support both ways up
• Your app doesn't nest popovers, i.e., selecting something on a popover should not display another popover
• Your app doesn't show more than one popover at a time

Submission package details

• The name of your app (in the binary package) matches (or is the abbreviated version of) its iTunes name
• Your iTunes description accurately describes the functionality of the app, i.e., it works as advertised
• Your iTunes description does not state the price
• Your iTunes description (and the binary) does not include the names of any competing platforms (e.g., Android or Blackberry)
• Your iTunes description does not mention unreleased iOS version numbers
• Your iTunes keywords match the functionality of the app
• Your iTunes keywords do not contain the names of other apps
• If your app's price is over $100, or it has in-app purchases over $100, it is rated 17+
• The screenshots do not include error states
• The categories the app is in match its functionality
• Any Easter eggs in the app are innocuous and are disclosed in the 'demo account' field
• Icons are provided for each of the required sizes
• All different sizes of icons contain the same artwork
• Version number (bundle version number) is >= 1.0
• The required-device-capabilities entry in the info.plist file match the requirements of the app
• Your app matches your claimed OS version compatibility
• NSZombieEnabled is set to NO