Hi everybody,
calling drush --debug cc all I noticed the warnings:

Use of undefined constant MENU_DYNAMIC_ITEM - assumed 'MENU_DYNAMIC_ITEM' ipauth.module:182
Use of undefined constant MENU_DYNAMIC_ITEM - assumed 'MENU_DYNAMIC_ITEM' ipauth.module:266

The according code in ipauth_menu() says:

  $items['admin/user/ip_authenticator/data/get_auths/%'] = array(
    'title' => t('IP Authenticator -- ajax'),
    'page callback' => 'ipauth_ajax',
    'page arguments' => array(5),
    'access callback' => 'user_access',
    'access arguments' => Array('administer ip_authenticator'),
    'file' => 'ipauth.admin.inc',
    'type' => MENU_DYNAMIC_ITEM,
  );
  [...]
  $items['logout'] = array(
   'title' => 'Log out',
   'page callback' => 'user_logout',
   'access callback'  => 'display_logout',
   'weight' => 10,
   'file' => '../../../../modules/user/user.pages.inc',
   'type' => MENU_DYNAMIC_ITEM
  );

As far as I can tell MENU_DYNAMIC_ITEM was dropped in Drupal 6.
According to https://api.drupal.org/api/drupal/includes!menu.inc/constant/MENU_DYNAMI... it was defined in Drupal 5 as
define('MENU_DYNAMIC_ITEM', MENU_VISIBLE_IN_TREE | MENU_VISIBLE_IN_BREADCRUMB)

In D6 that's the same as MENU_NORMAL_ITEM - see includes/menu.inc:
define('MENU_NORMAL_ITEM', MENU_VISIBLE_IN_TREE | MENU_VISIBLE_IN_BREADCRUMB);

Note that I did not experience any problems - it just seemed odd to me.
In my opinion using the string 'MENU_DYNAMIC_ITEM' instead of 0x0002 | 0x0004 does smell funny...

Can we just replace the two occurences of MENU_DYNAMIC_ITEM with MENU_NORMAL_ITEM?