Starting in JDK 23, the following program behaves differently when -Djava.locale.useOldISOCodes=true is set.

```
import java.util.List;
import java.util.Locale;

class T {
  public static void main(String[] args) {
    for (String l : List.of("iw", "fa", "iw")) {
      Locale locale = new Locale(l);
      Locale.setDefault(locale);
      String displayName = locale.getDisplayName();
      System.err.println(locale);
      System.err.println(displayName);
      System.err.println(Character.getDirectionality(displayName.charAt(0)));
    }
  }
}
```

$ java -fullversion
openjdk full version "22.0.2+9-70"
$ java -Djava.locale.useOldISOCodes=true T
iw
עברית
1
fa
فارسی
2
iw
עברית
1

$ java -fullversion
openjdk full version "23-ea+34-2361"
$ java -Djava.locale.useOldISOCodes=true T
iw
Hebrew
0
fa
فارسی
2
iw
Hebrew
0