  We are presenting here the new formulae for Bose-Einstein correlations (BEC)
which contain effects of final state interactions (FSI) of both strong (in
$s$-wave) and electromagnetic origin. We demonstrate the importance of FSI in
BEC by analysing data for $e^+e^-$ annihilation and for heavy collisions. The
inclusion of FSI results in the practical elimination (at least in $e^+e^-$
data) of the so called degree of coherence parameter $\lambda$ (which becomes
equal unity) and the long range parameter $\gamma$ (which is now equal zero).
