  The NEXT-White (NEW) detector is currently the largest radio-pure
high-pressure xenon gas time projection chamber with electroluminescent readout
in the world. NEXT-White has been operating at Laboratorio Subterr\'aneo de
Canfranc (LSC) since October 2016. This paper describes the calibrations
performed with $^{83m}\mathrm{Kr}$ decays during a long run taken from March to
November 2017 (Run II). Krypton calibrations are used to correct for the finite
drift-electron lifetime as well as for the dependence of the measured energy on
the event position which is mainly caused by variations in solid angle
coverage. After producing calibration maps to correct for both effects we
measure an excellent energy resolution for 41.5 keV point-like deposits of
(4.553 $\pm$ 0.010 (stat.) $\pm$ 0.324 (sys.)) % FWHM in the full chamber and
(3.804 $\pm$ 0.013 (stat.) $\pm$ 0.112 (sys.)) % FWHM in a restricted fiducial
volume. Using naive 1/$\sqrt{E}$ scaling, these values translate into
resolutions of (0.516 $\pm$ 0.0014 (stat.) $\pm$ 0.0421 (sys.)) % FWHM and
(0.4943 $\pm$ 0.0017 (stat.) $\pm$ 0.0146 (sys.)) % FWHM at the
$Q_{\beta\beta}$ energy of xenon double beta decay (2458 keV), well within
range of our target value of 1%.
