1. The carrier or maker issues it.
2. You decide to root it and head to xda forums (I don't offer rooting support anywhere.)
Keep in mind that no one I know offers support for this but I have done other models with some research of the xda forums.
i have a samsung galaxy i9300. and i want to upgrade its android version is v4.0.4. and now, tell me can i upgrade its latest version or not...??
if so then how can i do it.......??