how can I force an update to WordPress feed

WordPress supports external feeds, and parse the feed using a function named fetch_feed() from SimplePie. But fetch_feed caches results for 12 hours by default.

Is there any filter that we can use to make feed updates quicker? Yes, it is easy to do. Just copy the following codes and paste to your function.php of the active theme.

add_filter( 'wp_feed_cache_transient_lifetime', function(){ return 60;//seconds });