  The universal radiative corrections common to neutron and super-allowed
nuclear beta decays (also known as ``inner'' corrections) are revisited in
light of a recent dispersion relation study that found $+2.467(22)\%$,
i.e.~about $2.4\sigma$ larger than the previous evaluation. For comparison, we
consider several alternative computational methods. All employ an updated
perturbative QCD four-loop Bjorken sum rule (BjSR) defined QCD coupling
supplemented with a nucleon form factor based Born amplitude to estimate
axial-vector induced hadronic contributions. In addition, we now include
hadronic contributions from low $Q^2$ loop effects based on duality
considerations and vector meson resonance interpolators. Our primary result,
$2.426(32)\%$ corresponds to an average of a Light Front Holomorphic QCD
approach and a three resonance interpolator fit. It reduces the dispersion
relation discrepancy to approximately $1.1\sigma$ and thereby provides a
consistency check. Consequences of our new radiative correction estimate, along
with that of the dispersion relation result, for CKM unitarity are discussed.
The neutron lifetime-$g_A$ connection is updated and shown to suggest a shorter
neutron lifetime $< 879$ s. We also find an improved bound on exotic,
non-Standard Model, neutron decays or oscillations of the type conjectured as
solutions to the neutron lifetime problem, $\text{BR}(n\to \text{exotics}) <
0.16 \%$.

High Energy Physics - Phenomenology;Nuclear Experiment;Nuclear Theory