Upgrade Samsung Galaxy II OS to android 4.0?
I want to know if there is any official documentation on how to upgrade Samsung's Android enabled devices?
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I assume your device is not rooted since you did not mention it. For non-rooting device you just have to wait for the Over The Air (OTA) update from Samsung or your network provider.
Ota is definitely going to be the "easiest" but you aren't guaranteed to ever get the update. If you want to get ICS as soon as possible, I'd recommend flashing CyanogenMod (full update guide for the S2), downloads are here. Believe version CM9 is ICS 4.0.4, and CM10 (aka. Jelly Bean) is also available as nightly builds. I've heard some great things about it.
But... that may not be what you are looking for if you are trying to go completely stock...