  The IceCube neutrino observatory has established the existence of an
astrophysical diffuse neutrino component above $100$ TeV. This discovery was
made using the high-energy starting event sample, which uses the outer layer of
instrumented volume as a veto to significantly reduce atmospheric background.
We present the latest astrophysical neutrino flux measurement using high-energy
starting events. This latest iteration of the analysis extends the sample by
$1.5$ years for a total of $7.5$ years, updates the event properties with newer
models of light transport in the glacial ice, and has an improved systematic
treatment. As part of this new analysis, we report on compatibility of our
observations with detailed isotropic flux models proposed in the literature as
well as the standard generic models such as single, double power-law scenarios.
We find that none of the tested models are substantially preferred with respect
to a single power law.
