Many changes in iOS 6 are squirreled away in the Settings app--if, like most users, you don't delve into Settings, you'll miss some great new features. Here's a look at the changes to this important-but-overlooked app, organized in the order the sections appear on the Settings screen. (Though the screenshots here show an iPhone, I describe changes for all iOS devices.)
Minor reorganization As often happens with major updates to iOS, Apple has reordered a number of top-level settings items. For example, Twitter has been into a new group with the new Facebook item, and Notes has moved lower in the Settings screen.
New top-level items In a welcome change for many users, Bluetooth is now a top-level item in the Setting screen, grouped with Airplane Mode and Wi-Fi, for easier access. In addition, while you'll still need to use this Bluetooth item to pair headsets, speakers, and similar accessories, apps that use particular Bluetooth devices--for example, fitness apps that connect to a Bluetooth 4.0 heart-rate monitor--can now let you pair with those devices directly from within the app, without requiring a visit to the Settings app.
Reminders is also now a top-level item, providing the same options (which items to sync, and choosing a default list) as it did within the Mail, Contacts, Calendars screen in iOS 5.
Notifications and Do Not Disturb The Notifications item is now grouped with a new Do Not Disturb setting that silences notifications and incoming phone calls--or, in the case of an iPad or iPod touch, FaceTime calls. (When Do Not Disturb is enabled, a moon icon appears in the status bar.)
Though you can manually enable Do Not Disturb mode here, a number of useful options are found in a new Do Not Disturb screen accessed within Notifications. Here you can choose specific contacts (or groups of contacts) whose calls won't be silenced, and you can enable the Repeated Calls option, which bypasses Do Not Disturb mode if the same person calls twice within three minutes. The Repeated Calls option is useful if, or example, someone is trying to reach you because of an emergency. Finally, you can schedule Do Not Disturb to turn on and off at specific times, such as on at 11:00pm and off at 7:30am.
Some users also get new settings in the Notifications screen--at the bottom, grouped under Government Alerts--for enabling or disabling AMBER Alerts and Emergency Alerts. In our testing in the San Francisco Bay Area, Sprint and Verizon users see these settings, while AT&T users do not. However, the availability of these settings also appear to depend on your location: Responses to an informal poll of Twitter users indicate that Verizon users in some parts of the country get the settings, but those in other locations do not.
Privacy Location Services has been moved inside a new Privacy screen that lets you fine-tune access to Contacts, Calendars, Reminders, Photos, Bluetooth Sharing, and your Twitter and Facebook accounts. For each type of data, you can choose which apps have access to that data. The Location Services section of Privacy also gains a couple new settings, found in its System Services screen: toggles for Genius For Apps and Wi-Fi Networking.
Sounds In the Sounds screen on the iPhone, the two Vibrate toggles, previous split between a Silent section and the Ringer and Alerts section, are now grouped together as Vibrate On Ring and Vibrate On Silent. You can also now choose an alert tone for new-Facebook-post notifications, and you can choose one of seven preset vibration patterns, or create a custom vibration pattern, for each type of notification; these vibration patterns are in addition to each alert's audible tone. (You can also create and assign vibration patterns for individual contacts, but that's done in the Contacts app.)
On the iPad, the Sounds item is now at the top level of the Settings app--it was previously buried in the General screen.
Brightness & Wallpaper On the iPhone and iPod touch, the previously separate Brightness and Wallpaper items have been combined into a single Brightness & Wallpaper item that includes the same options for each as before. (Brightness & Wallpaper was already a single item on the iPad in iOS 5.)
General Apple has introduced a slew of changes in the General screen. For starters, it no longer contains the Bluetooth option (which, as noted above, has been moved to its own item in the main Settings list). On the iPad, iOS 6 removes the Network item and moves the VPN section up one level--the other items under Network in iOS 5 (Wi-Fi and Personal Hotspot) have their own top-level entries.
On the iPhone, the Network item has been renamed Cellular, and new here is a group of settings that let you choose which features (iCloud Documents, iTunes, FaceTime, Passbook Updates, and Reading List) can use cellular data. Note that to allow FaceTime to use cellular data, you must have an eligible cellular plan--AT&T, for example, requires that you subscribe to one of the company's Mobile Share plans in order to use this feature.
On iPads, the Usage screen now includes information on usage and standby time since the last full charge (options that were previously available only on the iPhone).
The Auto-Lock screen has gained a Never setting on all devices, and a 15-minute setting on the iPad. On the iPhone, the Require Passcode option in the Passcode Lock screen has gained settings for 15 minutes, 1 hour, and 4 hours. (Interestingly on an iPad 2, this screen actually loses a few options.) On iPhones, there are also new options to allow Passbook access when the device is locked, and to allow you to use iOS 6's new Reply With Message feature (see Phone, below) when the phone is locked.
The Restrictions screen no longer includes an option to allow YouTube, since iOS 6 no longer includes the YouTube app. However, it gains such an option for the iBookstore, and there's also a new Books option under Allowed content that lets you choose whether or not to allow books with explicit sexual content. The Allow Changes options now include one for locking the phone's volume limit (previously located in Settings -> Music -> Volume Limit), and the Location item has been moved into a new Privacy section that mirrors the options in the new top-level Privacy settings; for each type of data, you can choose whether or not to allow changes, as well as decide which apps have access to that data. (You can change many of these settings in the top-level Privacy, Twitter, and Facebook screens, though you can't access those screens if restrictions on them are enabled.)