  The air shower simulation code CORSIKA has served as a key part of the
simulation chain for numerous astroparticle physics experiments over the past
decades. Due to retirement of the original developers and the increasingly
difficult maintenance of the monolithic Fortran code of CORSIKA, a new air
shower simulation framework has been developed over the course of the last
years in C++, called CORSIKA 8. Besides the hadronic and muonic component, the
electromagnetic component is one of the key constituents of an air shower. The
cascade producing the electromagnetic component of an air shower is driven by
bremsstrahlung and photoproduction of electron-positron pairs. At ultrahigh
energies or in media with high densities, the bremsstrahlung and pair
production processes are suppressed by the Landau-Pomeranchuk-Migdal (LPM)
effect, which leads to more elongated showers compared to showers without the
LPM suppression. Furthermore, photons at higher energies can produce muon pairs
or interact hadronically with nucleons in the target medium, producing a muon
component in electromagnetic air showers. In this contribution, we compare
electromagnetic showers simulated with the latest Fortran version of CORSIKA
and CORSIKA 8, which uses the library PROPOSAL for the electromagnetic
component. While earlier validations of CORSIKA 8 electromagnetic showers
focused on showers of lower energy, the recent implementation of the LPM
effect, photo pair production of muons, and of photohadronic interactions
allows now to make a physics-complete comparison also at high energies.
