This is untrue.
They haven't updated the camera in the iPhones since the 4S.
Minor refinements, I know. It's still largely the same 8MP iSight sensor. The 5 has a pretty bad reputation for that sapphire lens causing a bad blue/purple tinge to images.
The S5 Mini could be bringing out a 13MP sensor with the processing power and OS to use it fully, something the 5S could already be doing.