apple they should announce that iphone 4s different design than iphone 4 even 1 small change still different
You should not assume that an accessory made for an older product will automatically fit a newer one. In fact there are at least 3 changes that might cause cases for an iPhone 4 to be unsuitable for a 4S:
1. Mute switch - same location as CDMA iPhone 4 but moved as compared to GSM iPhone 4. Many case designs were already redone to accommodate this after the CDMA phone was released in February 2011.
2. Camera changes - Differences are subtle, but some cases appear to be moving to larger cutouts due to image washout when flash is used (flash reflecting off the case cutout edges). I'm not finding definitive information on what exactly is different with the 4S that makes this necessary; might just be the more sensitive sensor (as opposed to a brighter flash).
3. Front ambient sensor - If a case is full-coverage (specifically if it covers the area above the touchscreen), then it may not have a properly positioned cutout for the ambient light sensor on the 4S - which was relocated slightly from the 4.
So in a nutshell - if you're looking at a bumper case, if it fits the CDMA iPhone 4 it will fit the 4S. If you're looking at a back/side coverage, some older cases (thicker material) might cause flash washout. For full-coverage, make sure the case is specifically designed or approved for the 4S.
