  We consider exceptional APN functions on ${\bf F}_{2^m}$, which by definition
are functions that are not APN on infinitely many extensions of ${\bf
F}_{2^m}$. Our main result is that polynomial functions of odd degree are not
exceptional, provided the degree is not a Gold member ($2^k+1$) or a
Kasami-Welch number ($4^k-2^k+1$). We also have partial results on functions of
even degree, and functions that have degree $2^k+1$.
