  Context. Detecting and characterizing substellar companions for which the
luminosity, mass, and age can be determined independently is of utter
importance to test and calibrate the evolutionary models due to uncertainties
in their formation mechanisms. HD 19467 is a bright and nearby star hosting a
cool brown dwarf companion detected with RV and imaging, making it a valuable
object for such studies. Aims. We aim to further characterize the orbital,
spectral, and physical properties of the HD 19467 system. Methods. We present
new high-contrast imaging data with the SPHERE and NaCo instruments. We also
analyze archival data from HARPS, NaCo, HIRES, UVES, and ASAS. We also use
proper motion data of the star from Hipparcos and Gaia. Results. We refine the
properties of the host star and derive an age of 8.0$^{+2.0}_{-1.0}$ Gyr based
on isochrones, gyrochronology, and chemical and kinematic arguments. This
estimate is slightly younger than previous estimates of ~9-11 Gyr. No orbital
curvature is seen in the current imaging, RV, and astrometric data. From a
joint fit of the data, we refine the orbital parameters for HD 19467B: period
398$^{+95}_{-93}$ yr, inclination 129.8$^{+8.1}_{-5.1}$ deg, eccentricity
0.56$\pm$0.09, longitude of the ascending node 134.8$\pm$4.5 deg, and argument
of the periastron 64.2$^{+5.5}_{-6.3}$ deg. We assess a dynamical mass of
74$^{+12}_{-9}$ MJ. The fit with atmospheric models of the spectrophotometric
data of HD 19467B indicates an atmosphere without clouds or with very thin
clouds, an effective temperature of 1042$^{+77}_{-71}$ K, and a large surface
gravity of 5.34$^{+0.08}_{-0.09}$ dex. The comparison to model predictions of
the bolometric luminosity and dynamical mass of HD 19467B, assuming our system
age estimate, indicates a better agreement with the Burrows et al. models;
whereas the other evolutionary models used tend to underestimate its cooling
rate.
