Federer's service motion changed from early days ?

I only got to watch small portions of video clips from his
junior and early pro days. So I could be wrong but
his serving motion has gotten simpler considerably
compared to early days ! His serving motion of early days
seem to have
a lot more coiling/hip stretch and even a slight
delay in winding up, kinda reminding me of Sampras
Does anyone know if he intentionally simplified it or
if he had any injury ???
This reminds me, there was an article on serve in Tennis magazine and it used Federer(in one of those 5-7 frame analysis) as an example, does anyone know which issue that was? I think it was almost a year ago though.


Cigo, I believe it was the November 2002 issue of tennis magazine. John McEnroe was on the cover.