Rossmann's simple-pole conjecture for nilpotent algebra zeta functions

Let $\mathfrak{O}$ be the coefficient ring, let $A$ be an $n$-dimensional nilpotent $\mathfrak{O}$-algebra, and write $\zeta_A(t)$ and $\zeta^{\lhd}_A(t)$ for its subalgebra and ideal zeta functions. Let $\binom{\infty}{n-1}_q=\frac{1}{(1-q)\dots(1-q^{n-1})}$. Rossmann's simple-pole conjecture. Both $\zeta_A(t)$ and $\zeta^{\lhd}_A(t)$ have a simple pole at $t=1$, with residue $\binom{\infty}{n-1}_q$. This refines the pole-existence conjecture for nilpotent algebras; the supplied text notes that the additional nilpotence requirement is essential and gives no indication that the conjecture itself has been resolved.