  We discuss sum-rule determinations of $\alpha_s$ from non-strange hadronic
$\tau$-decay data. We investigate, in particular, the reliability of the
assumptions underlying the "truncated OPE strategy," which specifies a certain
treatment of non-perturbative contributions, and which was employed in Refs.
[1-3]. Here, we test this strategy by applying the strategy to the $R$-ratio
obtained from $e^+e^-$ data, which extend beyond the $\tau$ mass, and, based on
the outcome of these tests, we demonstrate the failure of this strategy.We then
present a brief overview of new results on the form of duality-violating
non-perturbative contributions, which are conspicuously present in the
experimentally determined spectral functions. As we show, with the current
precision claimed for the extraction of $\alpha_s$, including a representation
of duality violations is unavoidable if one wishes to avoid uncontrolled
theoretical errors.
