how can i update ios7.0
I suspect you have a 4G iPod. As Apple said in June, iOS 7 is not compatible with the 4G iPod.
All the iOS devices compatible (iPhone 4 and later, iPad 2 and later, and 5G iPod touch) with iOS 7 have at least 512 MB of memory (RAM). The 4G iPod only has 256 MB
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