To use the Roland GO:MIXER PRO-X, your smartphone must meet the following requirements.
Android devices
A USB-C port that supports USB-OTG (On-The-Go), and a headphones jack
Android 9 or later
To check if your device supports USB-OTG, contact your device manufacturer or carrier.
iOS devices
A Lightning port or USB-C port, and a headphones jack
iOS 13 or later
For the current, full list of verified compatible smartphones, see Smartphone Compatibility.