On isomorphisms of circulant digraphs of bounded degree

C.H. Li recently made the following conjecture: Let ΓΓ be a circulant digraph of order n=n1n2n=n1n2 and degree mm, where gcd(n1,n2)=1gcd(n1,n2)=1, n1n1 divides 4k4k, where kk is odd and square-free, and every prime divisor of n2n2 is greater than mm, or, if ΓΓ is a circulant graph, every prime divisor of n2n2 is greater than 2m2m. Then ΓΓ is a CI-digraph of ZnZn. In this paper we verify that this conjecture is true.