Square has sent an email out to its users noting that they may have to make some slight settings changes if they want to continue using the Square credit card reader on their iPhone. The changes come from a new security setting in iOS 7 in which the user needs to grant each app access to the microphone or else the app will not be able to use it -- or anything that's plugged into it, like the Square reader.
The email lays out the steps users must take to approve 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.
Though this email addresses how to approve Square Register, you follow the exact same steps for any other app that needs microphone access. You'll only have to go through these steps for existing apps on your iPhone that were on it before you updated to iOS 7. Any new apps you download will prompt you to give them access to your microphone the first time you launch them.