Final Results of the MAJORANA DEMONSTRATOR's Search for Double-Beta Decay of ${}^{76}$Ge to Excited States of ${}^{76}$Se

${}^{76}$Ge can $\beta \beta$ decay into three possible excited states of ${}^{76}$Se, with the emission of two or, if the neutrino is Majorana, zero neutrinos. None of these six transitions have yet been observed. The MAJORANA DEMONSTRATOR was designed to study $\beta \beta$ decay of ${}^{76}$Ge using a low background array of high purity germanium detectors. With 98.2 kg-y of isotopic exposure, the DEMONSTRATOR sets the strongest half-life limits to date for all six transition modes. For $2\nu \beta \beta$ to the $0_1^{+}$ state of ${}^{76}$Se, this search has begun to probe for the first time half-life values predicted using modern many-body nuclear theory techniques, setting a limit of $T_{1\mathrm{/}2}>1.5\times {10}^{24}$ y (90% CL).