  The T2K experiment reports updated measurements of neutrino and antineutrino
oscillations using both appearance and disappearance channels. This result
comes from an exposure of $14.9~(16.4) \times 10^{20}$ protons on target in
neutrino (antineutrino) mode. Significant improvements have been made to the
neutrino interaction model and far detector reconstruction. An extensive set of
simulated data studies have also been performed to quantify the effect
interaction model uncertainties have on the T2K oscillation parameter
sensitivity. T2K performs multiple oscillation analyses that present both
frequentist and Bayesian intervals for the PMNS parameters. For fits including
a constraint on \ssqthonethree from reactor data and assuming normal mass
ordering T2K measures $\sin^2\theta_{23} = 0.53^{+0.03}_{-0.04}$ and
$\Delta{}m^2_{32} = (2.45 \pm 0.07) \times 10^{-3}$ eV$^{2}$c$^{-4}$. The
Bayesian analyses show a weak preference for normal mass ordering (89%
posterior probability) and the upper $\sin^2\theta_{23}$ octant (80% posterior
probability), with a uniform prior probability assumed in both cases. The T2K
data exclude CP conservation in neutrino oscillations at the $2\sigma$ level.
