Yes you can, but expect some iOS functionalities that are on, say the iPhone 5S won't carry over to the iPhone 4.
Sadly, no. The latest version of the 3rd iPhone (iPhone 3GS) is iOS 6.1.5.
The iPhone 5 will run iOS 6 or iOS 7.
Yes, you can run iOS 7 on the iPhone 4.
Since ios 7 is designed for the iphone 5, it will probably make the iphone 4 slower.
iOS 6 is the software that was launched with the iPhone 5. You can run this software version on an iPod Touch (4th or 5th gen), any iPad except the original, and the iPhone 3GS, 4, 4S, and 5. You have only this summer to update to it if your device is eligible for an update to iOS 7 coming this fall. If you are running iOS 5, you can update to it from Settings>General>Software Update. If you are running any older iOS, you must plug your device into an iTunes-authorized computer to update. The update is entirely free by the way. You can see more about what features it brings on Apple's website.
iOS 6 came out of beta September 21, 2012 with the launch of the iPhone 5. You can update to the latest iOS 6.1.3 (6.1.4 with the iPhone 5) by going into Settings>General>Software Update or plugging your device into an iTunes authorized computer if you are running anything older than iOS 5. If you are not fond of the iOS 7 update, then you must update to iOS 6 before this fall because after that, Apple forces you to only update to the latest software version or not at all. But you don't have to worry about this is you have a 4th gen iPod Touch or iPhone 3GS which can't get iOS 7.
The current latest iOS version on the iPhone 4S is iOS 6.1.3 considering iOS 6.1.4 is for the iPhone 5 only. iOS 7 will be available for the iPhone 4S this fall.
Yes.You can install iOS 7 on your iPhone 4.If at home in Wi-Fi, you can do so now in Setting>General>Software Update.
You can update the following Apple products to iOS 7 legally:iPhone 4iPhone 4SiPhone 5iPod touch (5th generation)iPad 2new iPad (3rd generation iPad)iPad with Retina display (4th gen)iOS 7 is already preinstalled on all of these devices if you have not purchased one yet. The iPhone 5S and 5C must run iOS 7.
The only iPod that can run iOS 7 is the 5th generation iPod Touch.
iOS 7 Can't run on an iPad 1. The hardware is simply not powerful enough to run the operating system. I believe iOS 5 is the newest OS that will run on the original iPad.
Yes, but some people said that iOS 7 will cause the phone run less smoothly.