The IMS (IP Multimedia Subsystem) is a classic example of a technology which spent many years desperately seeking an application. The promises of an IMS, supporting a huge range of IP services flexibly and dynamically, were discussed at length, but the complexity and cost of the platform deterred the majority of operators from investing. There were many use cases, but none compelling enough, until Voice over LTE became essential for many MNOs to roll out. Just as the need for migration to IP-based voice has driven mass adoption of IMS – plus cheaper, more manageable deployment options, including cloud-based services – the mobile services platform is shifting again in anticipation of 5G, and the IMS will have to be reinvented…