iPod touch Can I upgrade Ipt gen2 (2.1.1) to iOS4?

I have Ipod touch 2nd gen 16gb (2.1.1) and I am planning to upgrade it to newer version. Here I have some questions to ask.

1. Can I still upgrade this old version to iOS4?
if yes, which version of iOS4 can I upgrade to? (4.1?4.2?)
How can I do that with itunes?
2. Will my ipod touch get slower after the upgrade? I am not sure if it can still work smoothly/properly after the upgrade.
3. If there was problem, can I downgrade back to 2.1.1?

Thanks, I need your help!

miles01110 said:

No. Only iPod touches of the third generation or later are compatible.

http://www.apple.com/ios/

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Thanks.
So there is no chance to make the upgrade even to 4.1 or 4.2?

Nicolas4ever said:

You can update straight to iOS 4 .You can choose any version till the iOS 4.2.1

Click to expand...

thx, how can I do that? do I need to download the firmware of 4.2.1 first from somewhere online and make the update via itunes?