if a person's mobile phone was designed to work with 4g technology, what will happen when a 5g network is rolled out in their area?

If a person's mobile phone was designed to work with 4G technology, when a 5G network is rolled out in their area, their phone will continue to work on the 4G network. The phone will not be able to access or benefit from the 5G network, because 4G phones lack the necessary hardware to connect to 5G networks. The 4G network will still be supported and available for these devices for several years even after 5G rollout. To experience 5G speeds and features, the person would need to upgrade to a 5G-compatible phone. The presence of 5G does not cut off or deactivate 4G networks immediately; both networks often coexist for an extended period to serve devices with different capabilities.