We will update our continuum extrapolated result on the chiral
crossover temperature in QCD with (2+1)-flavor and physical quark
masses. Results are based on calculations with Highly improved
Staggered Quarks (HISQ) on three different lattices sizes (Nτ=6,8,12).
We systematically study all chiral second-order susceptibilities that
diverge in the ciral limit. From a Taylor expansion of these
susceptiblities up to forth-order we obtain the dependence of the
transition temperature on baryon, electric charge, and strangeness
chemical potentials. We also analyse fluctuations along the crossover
line. Finally we discuss universal scaling of the susceptibilities
with quark mass. From calculations with 5 values of the light quark
masses, that are up to a factor 6 smaller than physical, we estimate
the transition temperature in the chiral limit. Our results are
consistent with O(N) scaling and support the existence of a
true-second order phase transition in the chrial limit.