We report a measurement of electron antineutrino oscillation from the Daya Bay Reactor Neutrino Experiment with nearly 4 million reactor $\overline{\nu}_{e}$ inverse beta decay candidates observed over 1958 days of data collection. The installation of a Flash-ADC readout system and a special calibration campaign using different source enclosures reduce uncertainties in the absolute energy calibration to less than 0.5% for visible energies larger than 2 MeV. The uncertainty in the cosmogenic $^9$Li and $^8$He background is reduced from 45% to 30% in the near detectors. A detailed investigation of the spent nuclear fuel history improves its uncertainty from 100% to 30%. Analysis of the relative $\overline{\nu}_{e}$ rates and energy spectra among detectors yields $\sin^{2}2\theta_{13} = 0.0856\pm 0.0029$ and $\Delta m^2_{32}=(2.471^{+0.068}_{-0.070})\times 10^{-3}~\mathrm{eV}^2$ assuming the normal hierarchy, and $\Delta m^2_{32}=-(2.575^{+0.068}_{-0.070})\times 10^{-3}~\mathrm{eV}^2$ assuming the inverted hierarchy.

This work reports a precise measurement of the reactor antineutrino flux using 2.2 million inverse beta decay (IBD) events collected with the Daya Bay near detectors in 1230 days. The dominant uncertainty on the neutron detection efficiency is reduced by 56% with respect to the previous measurement through a comprehensive neutron calibration and detailed data and simulation analysis. The new average IBD yield is determined to be $(5.91\pm0.09)\times10^{-43}~\rm{cm}^2/\rm{fission}$ with total uncertainty improved by 29%. The corresponding mean fission fractions from the four main fission isotopes $^{235}$U, $^{238}$U, $^{239}$Pu, and $^{241}$Pu are 0.564, 0.076, 0.304, and 0.056, respectively. The ratio of measured to predicted antineutrino yield is found to be $0.952\pm0.014\pm0.023$ ($1.001\pm0.015\pm0.027$) for the Huber-Mueller (ILL-Vogel) model, where the first and second uncertainty are experimental and theoretical model uncertainty, respectively. This measurement confirms the discrepancy between the world average of reactor antineutrino flux and the Huber-Mueller model.