Sony’s older Xperia models used to support HDMI out, but for some inexplicable reason once Xperia phones started to adopt USB Type-C, it dropped support for HDMI/MHL output. None of the 2018 Xperia models, or older phones with USB Type-C supported HDMI/MHL output.
The good news is that Sony has finally brought back HDMI support with the Xperia 1. This means you can connect your Xperia 1 to an external display or TV which has an HDMI port using a USB-C to HDMI adapter cable. Similarly you can also connect to a monitor with DisplayPort using a USB-C to DisplayPort cable.
We’re not sure why Sony disabled the feature in older phones like the Xperia XZ Premium, Xperia XZ2 and Xperia XZ3 to name a few, but we’re glad the feature is back. We don’t know at this stage whether it plans to re-introduce the feature into older phones through a software update.
