Customize the “Registration complete. Please check your e-mail.” message on WP 4.0

How do we customize the “Registration complete. Please check your e-mail.” message that appears when registering on WordPress 4.0? In previous versions, Dave Ross solution worked:

add_filter( 'wp_login_errors', 'override_reg_complete_msg', 10, 2 );
function override_reg_complete_msg( $errors, $redirect_to ) {
   if( isset( $errors->errors['registered'] ) ) {
     $needle = __('Registration complete. Please check your e-mail.');
     foreach( $errors->errors['registered'] as $index => $msg ) {
       if( $msg === $needle ) {
         $errors->errors['registered'][$index] = 'Your new message';
       }
     }
   }

   return $errors;
}

Looking through wp-login.php, no changes have been made to the Filter the login page errors info. Why is the above code not working in WP 4?

If you need an alternative way, you can always hook into the login_init and modify the gettext filter:

add_filter( 'login_init',
    function()
    {
      add_filter( 'gettext', 'wpse_161709', 99, 3 );
    }
);

function wpse_161709( $translated_text, $untranslated_text, $domain )
{
    $old = "Registration complete. Please check your e-mail.";
    $new = "New text here";

    if ( $untranslated_text === $old )
    {         
        $translated_text = $new;
        remove_filter( current_filter(), __FUNCTION__ );
    }
    return $translated_text;
}

Update — The WP_Error class has changed:

There seems to be a change in the definition of the errors property of the WP_Errors class:

In WordPress version 3.9 we got this part:

var $errors = array();

but in WordPress version 4.0 it has been changed to:

private $error_data = array();

So the scope of this property has been changed from public to private.

That’s the reason why you can’t modify it directly in WordPress 4.0+.

… but you can instead use the magic __set and __get methods of the WP_Error class introduced in WordPress 4.0.

Then your code example could be modified to:

add_filter( 'wp_login_errors', 'wpse_161709', 10, 2 );

function wpse_161709( $errors, $redirect_to )
{
   if( isset( $errors->errors['registered'] ) )
   {
     // Use the magic __get method to retrieve the errors array:
     $tmp = $errors->errors;   

     // What text to modify:
     $old = __('Registration complete. Please check your email.');
     $new = 'Your new message';

     // Loop through the errors messages and modify the corresponding message:
     foreach( $tmp['registered'] as $index => $msg )
     {
       if( $msg === $old )
           $tmp['registered'][$index] = $new;        
     }
     // Use the magic __set method to override the errors property:
     $errors->errors = $tmp;

     // Cleanup:
     unset( $tmp );
   }  
   return $errors;
}

to change this particular error message.

Here are screenshot examples:

Before:

After: