Nothing that I have tried works on android 11 and earlier versions.
Because I tried using different approach but it doesn’t seem to be able to work on android 11 and earlier versions.
Even if is something that can only work on debug mode…
The best way to get unique identifier …
in Android: using unique_identifier to get IMEI
String identifier =await UniqueIdentifier.serial;
in IOS: Apple no longer allows you to retrieve the IMEI or any other device identification