Standard-action conjecture for $SL(2)$ over rings of integers

Let $k$ be a number field with ring of integers $\mathcal{O}$, and set $\Gamma=SL(2,\mathcal{O})$. The group $\Gamma$ is a lattice in

$$\prod_{i=1}^s SL(2,\mathbb{R})\times \prod_{i=1}^t SL(2,\mathbb{C}),$$

where $s$ and $t$ are the numbers of real and complex places of $k$, respectively. A hyperbolic $\Gamma$-space is standard if it is equivalent to $\mathbb{H}^2$ or $\mathbb{H}^3$ with one of the actions obtained by projection to a real or complex factor. A quasi-action is an action by quasi-isometries satisfying the group-action laws up to uniformly bounded error.

Standard-action conjecture. Every quasi-action by $\Gamma$ on a Gromov hyperbolic metric space either has an invariant horoball or is standard.

This conjecture predicts that, apart from actions preserving a horoball, all quasi-actions of $SL(2,\mathcal{O})$ on Gromov hyperbolic spaces arise from the natural actions on the hyperbolic planes or hyperbolic three-spaces associated with the archimedean factors. The supplied source does not state whether the conjecture is resolved.