  The finite remainder function for planar, color-ordered, maximally helicity
violating scattering processes in N=4 super Yang-Mills theory possesses a
non-vanishing multi-Regge limit that depends on the choice of a Mandelstam
region. We analyze the combined multi-Regge collinear limit in all Mandelstam
regions through an analytic continuation of the Wilson loop OPE. At leading
order, the former is determined by the gluon excitation of the
Gubser-Klebanov-Polyakov string. We illustrate the general procedure at the
example of the heptagon remainder function at two loops. In this case, the
continuation of the leading order terms in the Wilson loop OPE suffices to
determine the two-loop multi-Regge heptagon functions in all Mandelstam regions
from their symbols. The expressions we obtain are fully consistent with recent
results by Del Duca et al.
