  We consider scenario of the dark matter consisting of two fractions, stable
part being dominant and a smaller unstable fraction, which has decayed after
the recombination epoch. It has been suggested in Ref. [arxiv:1505.03644] that
the above scenario may alleviate tension between high-redshift (CMB anisotropy)
and low-redshift (cepheid variables and SNe Ia, cluster counts) cosmological
measurements. We derive constraints on the heavy relics branching to
$q\bar{q}$, $e^+e^-$, $\mu^+\mu^-$, $\tau^+\tau^-$, $\nu_e\bar{\nu_e}$,
$\nu_\mu\bar{\nu_\mu}$, $W^+W^-$ and $\gamma\gamma$ in the above scenario by
comparison of the secondary $\gamma$ and $\nu$ fluxes produced by the process
with recent diffuse $\gamma$ and $\nu$ flux measurements.
