  We present a new version of the hadron interaction event generator Sibyll.
While the core ideas of the model have been preserved, the new version handles
the production of baryon pairs and leading particles in a new way. In addition,
production of charmed hadrons is included. Updates to the model are informed by
high-precision measurements of the total and inelastic cross sections with the
forward detectors at the LHC that constrain the extrapolation to ultra-high
energy. Minimum-bias measurements of particle spectra and multiplicities
support the tuning of fragmentation parameters. This paper demonstrates the
impact of these changes on air shower observables such as $X_{\rm max}$ and
$N_\mu$, drawing comparisons with other contemporary cosmic ray interaction
models.

High Energy Physics - Phenomenology;High Energy Astrophysical Phenomena