Im just wondering who it is that sends out the updates, is it the device manufacturer or network carrier.
Looking on this forum many people have newer versions than mine buy whrn I check it says my device is up to date.
It depends. If you have a Nexus device or a Google Play edition of the HTC One of the Galaxy S4 you will get your update fairly quickly directly from Google. If you got it from a carrier you have to wait on the carrier to see if and when they will update it. Same if you bought an unlocked phone directly from the manufacturer.