Apple released iOS 7.1.1 last week, and you'd be well advised to download it to your devices. You can do so over the air by going to Settings > General > Software Update. Or you can connect your device to your computer and do the update via the iTunes software. The update fixes important security issues as well as bugs. Most importantly for iPhone 5s owners, it reportedly helps to make Touch ID faster and more accurate. According to a detailed explanation on Cult of Mac, accuracy would decay over time. Quoting a Reddit user, the post explains how the update improves Touch ID: "With iOS 7.1.1 Apple now takes multiple scans of each position you place finger at setup instead of a single one and uses algorithms to predict potential errors that could arise in the future." In the past, if you didn't get a good scan during setup, it would later cause problems. The increased accuracy of the update results in a faster response because the phone needs to make fewer calculations while unlocking the phone.
According to an overview of the changes in 7.1.1 in International Business Times, the update also fixes issue with Bluetooth keyboards when VoiceOver is enabled. However, there have been mixed reports regarding whether the update fixes the problem of battery drain that cropped up with the arrival of 7.1. Some users report the problem fixed, but many say the problem remains. If you're experiencing battery drain on your iPhone, you might want to try a fix that worked for a friend of mine. He simply did a "hard reset" of his device by holding down the sleep/wake button and the Home button at the same time.