Unipotent polynomial monofibration conjecture

Let $F_n$ be a free group of rank $n$, let $\Gamma=F_n\rtimes_{\alpha}\langle trangle$ be a unipotent polynomial suspension, and let $F_m$ be a free group of rank $m$. Suppose that $\Gamma=F_m\rtimes_{\beta}\langle srangle$ is another unipotent polynomial fibration of $\Gamma$. Unipotent polynomial monofibration conjecture. Then $m=n$ and $[\alpha]$ and $[\beta]^{pm 1}$ are conjugate in ${\mathrm{Out}(F_n)}$. This conjecture asks whether the abstract suspension group retains the information about the unipotent polynomial automorphism, up to inversion and conjugacy; no resolution is supplied in the source.