  We analyze the existing rotation-curve data of the Milky Way and M31 galaxies
that extends to very large distances and low accelerations. We find a
systematic downward trend in the weak acceleration (large distances) segment of
the radial acceleration. A similar downward trend has been noticed in the
$\Lambda$CDM EAGLE simulation, while the deviation from the generic MOND
prediction would need to be ascribed to an external field effect, or possibly a
post facto selected acceleration function $\mu(x)$.
