  We confront the recent improved measurements of the D_{(s)} (semi) leptonic
decays with lattice QCD (LQCD) with n_f=3 flavours and QCD spectral sum rules
(QSSR) predictions. D\to\mu\nu_\mu leptonic width data compared with
theoretical determinations of f_D, leads to the value of the CKM mixing angle :
|V_cd|= 0.230 (10)_exp (9)_th. Measured ratio of the D semi-leptonic widths
combined with LQCD and QSSR predictions leads to the average |V_cd|/|V_cs|=
0.2175(88), and then to |V_cs|= 1.068(47). We consider the previous
determinations as improvements of the existing estimates. Using the average
data of the D_s\to \mu\nu_\mu (resp. D_s\to \tau\nu_\tau) branching ratios, one
obtains : |V_cs|f_{D_s}^\mu= (259 +- 12) {MeV} (resp) |V_cs|f_{D_s}^\tau= (274
+- 13) {MeV}, which can be compared with the average of the Standard Model (SM)
values from LQCD and QSSR f_{D_s}=(240 +- 7) MeV. If one uses the present
determination of |V_cs|, there is an agreement with the SM prediction within
1\sigma. If instead, we impose the unitarity constraint |V_cs|< 1, or assume
(as frequently done) |V_cs|=|V_ud|, we would obtain a deviation from the SM
expectations ranging from 1.5 to 3 \sigma, eventually signaling some New
Physics beyond the SM.
