Apple today seeded the first beta of iOS 14.5 to developers for testing, and a key new feature is global support for 5G in Dual-SIM mode on iPhone 12 models, as noted by Rene Ritchie. This functionality was previously only available in mainland China.
iPhone 12 models are equipped with both a physical SIM slot and a digital eSIM, allowing for a feature known as dual SIM, dual standby. This means you can have two lines of service on one iPhone, which is useful for purchasing data-only plans while traveling abroad or having personal and business lines on a single iPhone. Until now, Dual-SIM mode was limited to LTE, but iOS 14.5 introduces support for faster 5G on both lines.
Apple has previously said that iOS 14.5 will be released in the early spring, so the software update will likely become available in late March at the earliest. A public beta will likely be released within the next day or so.
An internal Verizon presentation obtained by MacRumors had indicated that Apple planned to enable 5G in Dual-SIM mode by the end of 2020, so the functionality is arriving a few months later than expected.