Different UITextFieldDelegate behavior in iOS 26 with shouldChangeCharactersInRanges

Scenario: Typing Chinese Zhuyin “ㄨㄤ” and then selecting the candidate word “王”.

• On iOS 18, the delegate (textField:shouldChangeCharactersInRange:replacementString:) is called with:
  • range: {0, 2}
  • replacementString: "王"
• On iOS 26, the delegate (textField:shouldChangeCharactersInRanges:replacementString:) instead provides:
  • ranges: [{2, 0}]
  • replacementString: "王"

This results in inconsistent text input handling compared to earlier system versions.

Implement: Limit user input to a maximum of 100 Chinese characters.

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    if ([textField markedTextRange]) {
        return YES;
    }
    NSString *changedString = [textField.text stringByReplacingCharactersInRange:range withString:string];
    if (changedString.length > 100) {
        return NO;
    }
    return YES;
}

Questions:

1. Is this an intentional change in iOS 26?
2. If intentional, what is the recommended way to handle such cases in order to support both iOS 18 and iOS 26 consistently?