  We update the fundamental physical and orbital properties of the transiting
hot-Saturn type exoplanet HAT-P-19b and its host star HAT-P-19 as a result of
the global modeling of our high-precision transit light curves, an archive
spectrum, radial velocity observations, brightness values from broadband
photometry in different passbands, and the precise distance of the system
derived from its Gaia parallax. We collected all the light curves obtained with
ground-based photometry by amateur and professional observers, measured
mid-transit times, analyzed their differences from calculated transit timings
based on reference ephemeris information, which we update as a result. We
haven't found any periodicity in the residuals of a linear trend, which we
attribute to the accumulation of uncertainties in the reference mid-transit
time and the orbital period. We discuss the potential origins of the variation
in transit timings briefly and find stellar activity as the most likely cause.
Finally, we comment on the scenarios describing the formation and migration of
this hot-Saturn type exoplanet with a bloated atmosphere yet a small core,
although it is orbiting a metal-rich ([Fe / H] = 0.24 dex) host star based on
the planetary, orbital, and stellar parameters of the system that we derived
from our global model, the age and the evolutionary history of the star.
