The antiProton Unstable Matter Annihilation (PUMA) experiment at CERN aims to study the edge of the nucleus through low-energy antiproton-nucleon reactions. To this end a transportable Penning-Malmberg trap has been constructed in CERN's Antimatter Decelerator (AD) facility. PUMA plans to trap and transport up to 10⁹ antiprotons to the ISOLDE facility, where exotic nuclei can be produced and isotopically purified in a newly constructed beamline at ISOLDE featuring a 30 keV Multiple Reflection TOF Mass Spectrometer (MR-TOF-MS). The PUMA trap consists of two distinct trapping regions: one for the storage of antiprotons for several months, and another for the mixing and collision of antiprotons with stable and radioactive ions. To enable the long-term trapping of antiprotons, the PUMA experiment aims for a pressure in the traps of 10⁻¹⁷ mbar.A time projection chamber surrounding the collision trap allows identification of the charged products of the reaction and therefore identifies whether a proton or nucleon annihilated with the antiproton. From this, the nucleonic composition of the surface of the nucleus is directly probed. The PUMA experiment therefore provides a new window on nuclear structure and the nuclear equation of state.  This talk provides an update on the commissioning of the PUMA experiment up to the CERN long shutdown. First results with antiproton trapping and ion mixing from the PUMA offline ion source will be shown.