An important open problem in quantum information concerns with the question whether entanglement between signal states can help to send classical information on quantum channels. Recently, Hasting proved that entanglement does help by finding a counter-example for the long standing additivity conjecture that the minimum von-Neumann entropy output of a quantum channel is additive under taking tensor products. In this talk I will show that the minimum von-Neumann entropy output of a quantum channel is locally additive. Hasting's counterexample for the global additivity conjecture, makes this result somewhat surprising. In particular, it indicates that the non-additivity of the minimum entropy output is related to a global effect of quantum channels. I will end with few related open problems.