The Drinfeld analogue of Ogg's Shimura-subgroup conjecture

Let $\mathfrak{p}$ be a prime of $A$, let $J_0(\mathfrak{p})$ be the Jacobian of the Drinfeld modular curve $X_0(\mathfrak{p})$, let $\mathcal{S}(\mathfrak{p})$ be the Shimura subgroup, and let $\mathcal{M}(\mathfrak{p})$ be the maximal $\mu$-type subgroup of $J_0(\mathfrak{p})$. Drinfeld Shimura-subgroup conjecture.

$$\mathcal{M}(\mathfrak{p})=\mathcal{S}(\mathfrak{p}).$$

This is the Drinfeld analogue of Ogg's conjecture for the Shimura subgroup. The supplied text says that this prime-level conjecture was proved by Ambrus Pál.