Without a doubt, one of the biggest highlights of yesterday’s WWDC 2012 keynote was iOS 6. Apple’s latest mobile operating system packs in over 200 new features, some of which we heard about at yesterday’s keynote, some of which have come to light as developers have gotten their hands on the new iOS 6 beta.

Of course, every update – be it iOS or OS X – has casualties. There is always a list of devices that aren’t supported. With OS X 10.8 Mountain Lion, if your computer was made before about the middle of 2009, you’re out of luck. With iOS, the compatibility list is actually pretty impressive. Most of Apple’s iOS device lineup will support iOS 6. Unfortunately “most” doesn’t mean “all,” and “support” doesn’t mean “run every new feature.” Fortunately, Apple has published a list of compatible devices and which features will be supported on each.

So, let’s start with the devices that won’t run iOS 6 at all. If you’re still rocking a first-generation iPad (like yours truly), then you’re out; iOS 6 only supports the iPad 2 and new iPad. On the iPhone front, only the first generation iPhone and the iPhone 3G are left out (in point of fact, the original iPhone lost support for new iOS versions quite some time ago). The list of compatible iPod Touch models is much smaller: anything older than the 4th generation iPod Touch (which came out in 2010) is out of luck.

Okay, so now you know your device is will support iOS 6, the big question is which features your device will run. Some of these are pretty obvious (like Siri), while others are less obvious. Here’s the list below:

Siri: On the iPhone, Siri remains an iPhone 4S exclusive. On the iPad, it will be available only on the new iPad (not the iPad 2).

FaceTime: To use FaceTime over a 3G connection, you have to have the iPhone 4S or the new iPad only (the cellular data model, naturally).

Mail VIP: Curiously, this requires the iPhone 4 or iPhone 4S, and the iPad 2 or new iPad.

Offline Reading List: Once again, the iPhone 3GS is left out. This feature is compatible with the iPhone 4 and iPhone 4S, and the second and third generation iPads.

Maps: Flyover and turn-by-turn navigation are limited to the iPhone 4S, the iPad 2, and the new iPad.

Shared Photo Streams: Yet again, no love for the iPhone 3GS. Once again, only compatible with the iPhone 4, iPhone 4S, iPad 2, or new iPad.

It’s worth noting that this is not an exhaustive list. In fact, this list comes from the footnotes of Apple’s iOS 6 preview page. Which means that if you put iOS 6 on your iPhone 4, iPhone 3GS, or iPad 2, you may still be in for some unwelcome surprises in terms of what your device will or won’t do with the new operating system.