  We present here the updated calibration of The Nuclear Spectroscopic
Telescope ARray NuSTAR, which was performed using data on the Crab accumulated
over the last 9 years in orbit. The basis for this new calibration contains
over 250ks of focused Crab (imaged through the optics) and over 500ks of
stray-light Crab (not imaged through optics). We measured an epoch averaged
Crab spectrum of the stray-light Crab data and define a canonical Crab spectrum
of Gamma = 2.103 +- 0.001 and N = 9.69 +- 0.02 keV-1 cm-2 s-1 at 1 keV, which
we use as our calibration standard. The new calibration, released in the CALDB
update 20211020, provides significant updates to: 1) the detector absorption
component, 2) the detector response function, and 3) the effective area
vignetting function. The calibration improves agreement between FPMA and FPMB
across detectors with a standard deviation of 1.7% for repeat observations
between off-axis angles of 1-4 arcmin, and the measured flux has increased by
5-15%, with 5% below 1 arcmin off-axis angle, 10% between 1-2 arcmin, and 15
above 4arcmin.
