Massive MIMO has been widely cited as a key technology with 5G mobile solutions and continues to be an active area in both research and product development domains, with promise of significant capacity and coverage extensions over SISO and low order MIMO systems. However, in mobile environments with highly variable and dynamic radio scattering conditions, the channel estimation problem is non-trivial, yielding degradation of performance in practical situations over theoretical estimates and lab results. Further, high order MIMO designs require high bandwidth backhaul connections. In parallel, RAN architectures are being reconsidered. With new open access protocols such as eCPRI, radio antenna arrays can be separated from baseband processing hubs and control plane systems using ethernet over fiber links, enabling centralised architectures which can support diverse MIMO and beamforming. This talk will review the current state of massive MIMO in mobile systems, the potential for MIMO evolution with centralised RANs, the potential for these technologies to support spectrum sharing, and the potential system and industry advantages.