What iOS 7 features are missing on the iPhone 4?
Apple's iPhone 4 is the oldest hardware supported by iOS 7. This means that iPhone 4 users can install the latest firmware, however some features are missing. The A4 processor inside the iPhone 4 was first released in March 2010, and is now several generations behind. Here is a list of major iOS 7 features that are missing due to slower processor speeds or missing hardware on the iPhone 4:
Panoramic camera mode
Live camera filter effects
Slow motion video recording
3D flyover in maps
Siri personal assistant
Live wallpapers, parallax and translucency effects