J. Simon's finiteness conjecture for epimorphisms of knot groups

Let $k \subset {\mathbb S}^3$ be a knot, and let $E(k)$ denote its exterior. Consider knots $k_i \subset {\mathbb S}^3$ whose exteriors are $E(k_i)$ and epimorphisms

$$\phi_i:\pi_1(E(k))\to\pi_1(E(k_i)).$$

J. Simon's finiteness conjecture. There are only finitely many knots $k_i \in {\mathbb S}^3$ for which such an epimorphism exists.

This problem concerns the finiteness of knot groups that are epimorphic images of a fixed knot group. The source presents it as a conjecture raised in the 1970s and does not state that it has been resolved in full.