We report on the status of our kaon semileptonic form factor calculations using the highlyimproved staggered quark (HISQ) formulation to simulate the valence fermions. We present results for the form factor f Kπ + (0) on the asqtad N f = 2 + 1 MILC configurations, discuss the chiral-continuum extrapolation, and give a preliminary estimate of the total error. We also present a more preliminary set of results for the same form factor but with the sea quarks also simulated with the HISQ action;

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... se results include data at the physical light quark masses. The improvements that we expect to achieve with the use of the HISQ configurations and simulations at the physical quark masses are briefly discussed.