There are different ways to disable WordPress updates. Below we will list how to disable updates manually in your site's wp-config.php file and with your functions.php file from your theme, as well as other plugin methods.

To disable automatic WordPress core updates, add the following line to your wp-config.php:

define( 'WP_AUTO_UPDATE_CORE', false );

Add the following to your active theme's functions.php file to disable plugin updates:

add_filter( 'auto_update_plugin', '__return_false' );

To turn off updates for themes, use this filter:

add_filter( 'auto_update_theme', '__return_false' );

An easy plugin to use in order to disable all WordPress updates for core, plugins and themes is Easy Updates Manager.

Another option is the plugin called Disable All WordPress Updates.