Apple released its new operating system Wednesday, and iOS 6 comes with a lot of changes and added features that are important to know about. Here’s a snapshot of the most notable of more than 200 new options that Apple has advertised for this upgrade.

First, you can update your Apple device to iOS 6 over the air by heading to the “General” menu and choosing “Software Update.”

But before you do, there are a few things you’ll want to consider, such as whether it’s smart to rush to upgrade today.

Why? Well, it could take some time. There are a lot of people trying to update their devices right now. For this post, I updated three Apple devices: One took just 20 minutes for a full update, and another just 25 minutes. But when I upgraded my iPhone, it had to be restarted and took nearly an hour.

Second, some of your apps will change when you upgrade. The most notable is Maps. Google has powered the iPhone’s maps app for years, but Apple has struck out on its own for this latest version of iOS. Reviews of the app have been mixed so far, as Apple’s map function is much earlier in its development than Google’s.

With an upgrade, you lose Google’s Street View. Apple’s Flyovers feature, which is supposed to give you a 3D feel of a city, is very limited. Note that it may not be available for a city near you quite yet, but you can check out the Flyovers for Sydney, London, New York or Boston.

The Maps app adds turn-by-turn navigation, which I haven’t had the chance to check properly while at my desk. Unlike its predecessors, Apple’s Maps reads out directions.

If you’re wedded to Google Maps, be aware that Google does not have a standalone maps app in the App Store right now. If you want to use that service, you’ll have to call it up on the browser.

Among the new perks, is a clock app for the iPad that can work as an alarm clock, stopwatch or timer. On the iPhone and iPod Touch, users will gain access to Passbook — Apple’s ticketing and loyalty card wallet app.

Third, if your device already had Siri, she’s new and improved, now able to open apps, make dinner reservations through Open Table, update Facebook and even check sports scores and standings.

Sadly, I won’t see Siri — old or new — on my iPad 2 or my 4th-generation iPod Touch, even though they’re both compatible with iOS 6. And I’ll again miss out on Apple’s handy dictation feature, either.

Since we’re on the subject of compatibility, users should know that Flyover and turn-by-turn navigation won’t work with the iPhone 4, iPhone 3GS or 4th-generation iPod Touch. And for owners of the iPhone 3GS and first-generation iPad, the iOS 6 will not work with their devices. At all.

Some additions work region by region. If you’re outside the United States, you should definitely check Apple’s iOS 6 feature availability list.

Apple has also redesigned The App Store and iTunes Store have been redesigned to move away from lists and toward grids. You’ll also be able to set a “Do not Disturb” period that will mute your calls and alerts, either immediately or on a schedule. You’ll also be able to allow certain callers even when you’re in the quieter mode or if you get a repeat call.

And now you’re even able to ignore calls, with a preset message or by setting a reminder to call that person back — a nice touch in an increasingly busy world.

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