The Germanium Detector Array (GERDA) collaboration's result of phase I of the detector was a limit of T β β β β 0 ν ν > 2.1 ⋅ ⋅ 10 25 years (90% C.L.). It used germanium both as source and detector material. Liquid argon was used for muon vetoing and as a shielding from background radiation. The Q -value of Ge for 0νββ decay is 2039 keV, but no excess of events in this region was found. Phase II of the experiment started data-taking in 2015, and it used around 36 kg of germanium for the detectors. The exposure analyzed until July 2020 was 10.8 kg yr. Again, no signal was found and thus a new limit was set to T β β β β 0 ν ν > 5.3 ⋅ ⋅ 10 25 years (90% C.L.). The detector has stopped working and published its final results in December 2020. No neutrinoless double beta decay was observed.