I have Ipod touch IOS 3.1.3 how to pass to IOS 4 or more ?

See the chart below to determine whether you can upgrade your device and what you can upgrade to. You cannot upgrade yours because it is an iPod Touch 1.

IPhone, iPod Touch, and iPad iOS Compatibility Chart

Device iOS Verson

iPhone 1 iOS 3.1.3

iPhone 3G iOS 4.2.1

iPhone 3GS iOS 6.1

iPhone 4 iOS 6.1

iPhone 4S iOS 6.1

iPhone 5 iOS 6.1

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iPod Touch 1 iOS 3.1.3

iPod Touch 2 iOS 4.2.1

iPod Touch 3 iOS 5.1.1

iPod Touch 4 iOS 6.1

iPod Touch 5 iOS 6.1

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iPad 1 iOS 5.1.1

iPad 2 iOS 6.1

iPad 3 iOS 6.1

iPad 4 iOS 6.1

iPad Mini iOS 6.1

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Select the method most appropriate for your situation.

Upgrading iOS

1. How to update your iPhone, iPad, or iPod Touch

2. iPhone Support

3. iPod Touch Support

4. iPad Support

a. Updating Your iOS to Version 6.0.x from iOS 5

Tap Settings > General > Software Update

If an update is available there will be an active Update button. If you are current,

then you will see a gray screen with a message saying your are up to date.

b. If you are still using iOS 4 — Updating your device to iOS 5 or later.

c. Resolving update problems

1. iOS - Unable to update or restore

2. iOS- Resolving update and restore alert messages

If you still want apps that will work on an ios 3.1.3 device try "Vintapps 3.1.3" in the Apple app store. About 25,000 available apps you can download right from your device.