Photoelectron (PE) spectra provide detailed insight into the electronic structure of atoms, molecules and solids. Hereby electron correlation and relativistic effects influence the structure of the PE spectrum in a complicated way necessitating a consistent theoretical treatment. By embedding the one-particle propagator technique in a four-component framework the interplay between relativistic and correlation effects can be described correctly. In this article the Dirac–Hartree–Fock algebraic diagrammatic construction scheme (DHF-ADC) together with recent applications is reviewed and fully relativistic PE spectra of SeH 2 and TeH 2 in combination with basis set studies are presented.