  We compute the radiation reacted momentum impulse $\Delta p_i^\mu$, spin kick
$\Delta S_i^\mu$, and scattering angle $\theta$ between two scattered spinning
massive bodies (black holes or neutron stars) using the $\mathcal{N}=1$
supersymmetric worldline quantum field theory formalism up to fourth
post-Minkowskian (4PM) order. Our calculation confirms the state-of-the-art
non-spinning results, and extends them to include spin-orbit effects. Advanced
multi-loop Feynman integral technology including differential equations and the
method of regions are applied and extended to deal with the retarded
propagators arising in a causal description of the scattering dynamics. From
these results we determine a complete set of radiative fluxes at sub-leading PM
order: the 4PM radiated four-momentum and, via linear response, the 3PM
radiated angular momentum, both again including spin-orbit effects.
