Proper treatment of convective boundaries in stellar evolution codes and their impact on the oscillation spectra of blue supergiants.

TESS will for the first time map the instability strip of B stars beyond the MS. It has been shown that the pulsationnal properties of B stars beyond the MS, which result from the presence (or not) of an ICZ (Intermediate Convection Zone), depend strongly on the behavior of the convective boundaries during the MS. Proper treatment of those boundaries is therefore very important. We show here the results of the recent improvements implemented in MESA to correctly position the boundaries of the convective regions.