A time string according to RFC 2822 must be formatted in English. Otherwise the interoperability with other systems can not be guaranteed. The drupal format_date function returns the time string in a customized language.
File "includes/common.inc", function "format_date":
else if ($c == 'r') {
$date .= format_date($timestamp - $timezone, 'custom', 'D, d M Y H:i:s O', $timezone, $langcode);
}
My suggestion is to replace $langcode by 'en_US'. This should resolve the problem. Unfortunately I have no working drupal 6 installation to test this.
Comments
Comment #1
Robin Millette commentedMakes sense to me. Doesn't affect Drupal 7 or 8 as they don't have a special case for 'r'.