How to stop showing wordpress Update notification message

Here is code to stop showing wordpress Update notification message.

Want to remove the nagging update notice from your WordPress site? Sometimes this can be helpful if you built the site for someone else and don’t want them upgrading it. Perhaps there are plugins running on the site that won’t be compatible with the update. Here’s a quick snippet to remove the notice from your site:

Just below code in your theme function.php file

add_filter( 'pre_site_transient_update_core', create_function( '$a', "return null;" ) );