  We revisit the status of the new-physics interpretations of the anomalies in
semileptonic $B$ decays in light of the new data reported by Belle on the
lepton-universality ratios $R_{D^{(*)}}$ using the semileptonic tag and on the
longitudinal polarization of the $D^*$ in $B\to D^*\tau\nu$, $F_L^{D^*}$. The
preferred solutions involve new left-handed currents or tensor contributions.
Interpretations with pure right-handed currents are disfavored by the LHC data,
while pure scalar models are disfavored by the upper limits derived either from
the LHC or from the $B_c$ lifetime. The observable $F_L^{D^*}$ also gives an
important constraint leading to the exclusion of large regions of parameter
space. Finally, we investigate the sensitivity of different observables to the
various scenarios and conclude that a measurement of the tau polarization in
the decay mode $B\to D\tau\nu$ would effectively discriminate among them.
