and Apple hasn't changed the way updates are done but,
That was a huge jump from 4.35 to 6.1.3 and probably had to be handled differently
I confess that I have not updated my iPhone4 in quite a while. Today I decided to join the 21st century and update from 4.3.5 to 6.1.3. The process was pretty slow and unlike previous updates I have done, after downloading and installing the update, it required that I restore my phone from back-up in iTunes. Then it required an iTunes synch. Did I do something wrong or is this the complicated way that Apple now handles updates?