static function upgrade()
{
Slickr_Flickr_Options::upgrade_options();
//save any new options on plugin update
delete_option(self::ACTIVATE_KEY);
//delete key so upgrade runs only on activation
Slickr_Flickr_Cache::clear_cache();
//clear out the cache
}
function clear_cache()
{
$_SERVER['REQUEST_URI'] = remove_query_arg('cache');
Slickr_Flickr_Cache::clear_cache();
$this->add_admin_notice(__('WordPress RSS cache', SLICKR_FLICKR_DOMAIN), __('has been cleared successfully', SLICKR_FLICKR_DOMAIN));
return true;
}
