  Gauge threshold corrections for intersecting D6-brane string models on
toroidal orbifold backgrounds are reconsidered. Both by dimensionally
regularising the appearing open string one-loop diagrams in tree-channel as
well as by zeta-function regularisation of the corresponding loop-channel
one-loop diagrams, we arrive at a result which takes into account the infrared
divergence from the contribution of the massless states in the running of the
gauge coupling constant as well as the contribution of states, which become
light in certain regions of the moduli space.
