DzsoniB wrote:I'm about to get an iPhone 3Gs used. The question: Can I update the iOS on that for a newer version, or Apple won't allow me.
The latest iOS for the iPhone is 5.1.1
The iPhone 3GS is compatible with this update. Take a look here
http://support.Apple.com/kb/DL1521Just download and install the latest iTunes, then use iTunes to update the iPhone.
Once the iPhone is connected to iTunes, iTunes should detect the latest iOS software available for your iPhone and start the download and install process.
You shouldn't have any problems, unless the iPhone has been blocked in anyway.