Unitriangularity of decomposition matrices of the unipotent $\mathrm{\ell }$-blocks for simple adjoint exceptional groups

In 2020, Brunat-Dudas-Taylor showed that the decomposition matrix of unipotent $\mathrm{\ell }$-blocks of a nite reductive group in good characteristic has unitriangular shape, under some conditions on the prime $\mathrm{\ell }$, in particular $\mathrm{\ell }$ being good. We extend this result to $\mathrm{\ell }$ bad by adapting their proof to include the $\mathrm{\ell }$-special classes dened by Chaneb.