Let G be a split adjoint group defined over Fq, let Fq(t), and let A be the adèles of F. We describe the local constituents at two points of automorphic representations of G in the discrete part of L2(G(F)\G(A)) which have vectors invariant under Iwahori subgroups at these two points and are unramified at all other points.
Amritanshu Prasad. "Almost unramified discrete spectrum for split groups over Fq(t)." Duke Math. J. 113 (2) 237 - 257, 1 June 2002. https://doi.org/10.1215/S0012-7094-02-11322-2