Merchants using the Square credit card reader who have upgraded to iOS 7 need to adjust some settings to continue using the reader on iPhones. Apple's new operating system includes a security setting requiring the user to grant each app access to the microphone. Without the setting change, the app can't use anything plugged into the mic jack.

Square has notified users about the needed adjustments and advised them of the steps required to approve the Square Register for microphone access:

When you update your Apple device to iOS 7, you may need to adjust your microphone in order to swipe payment cards with your card reader.

If you have already updated to iOS 7, please allow Square Register to access the microphone.

Here's how:

1. Go to Settings > Privacy > Microphone
2. Turn on the Square Register slider
3. Relaunch Square Register and swipe away!

If you have not yet updated to iOS 7, your app will function normally. When you do update, follow the prompt to allow microphone access the first time you open Square Register.

The same steps should be followed for any apps that use the microphone jack. The changes affect only apps that were on the phone before it was updated to iOS 7. Apps downloaded after the update is installed will provide a prompt when they're launched the first time.

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