So what?  How DARE you think that!  This, according to Apple is the biggest change to their portable device software in their history, so get ready, folks! 

Tech tallk extra   The new operating system for your iPHone and iPad  iOS 7

from YouTube and Apple, Inc
It's being called the biggest update in the history of the their portable devices.  When you download it, you probably won't recognize your phone or iPad
I can't really go into detail here, because there are so many, but the biggest thing they are replacing is anything familiar to you.  Anything that looks like something in real life is now gone, and that was what I liked about my phone.
Your calendar looked like a calendar - it has a little rip in the corner to pretend that you ripped off the previous month. When you played a podcast (of which there are millions) - a reel to reel recorder would come on your screen and the reels would turn.  The notepad is an actual yellow legal pad.  I loved that.  Supposedly they are changing all of it into a "flat design", whatever that means , so I'm looking forward to seeing what they are talking about.
Here's the official video from Apple that explains things
http://youtu.be/rT_OmTMwvZI
There are many more changes coming, and I hear that it will take awhile to learn.  Supposedly you can start downloading it today, but I personally would wait a day to make sure that there are no problems.   CNN, btw has a lot more information on the update
http://money.cnn.com/2013/09/18/technology/mobile/ios-7/