WP_Automatic_Updater::should_update( string $type, object $item, string $context )

	public function should_update( $type, $item, $context ) {
		// Used to see if WP_Filesystem is set up to allow unattended updates.
		$skin = new Automatic_Upgrader_Skin;

		if ( $this->is_disabled() )
			return false;

		// Only relax the filesystem checks when the update doesn't include new files
		$allow_relaxed_file_ownership = false;
		if ( 'core' == $type && isset( $item->new_files ) && ! $item->new_files ) {
			$allow_relaxed_file_ownership = true;
		}

		// If we can't do an auto core update, we may still be able to email the user.
		if ( ! $skin->request_filesystem_credentials( false, $context, $allow_relaxed_file_ownership ) || $this->is_vcs_checkout( $context ) ) {
			if ( 'core' == $type )
				$this->send_core_update_notification_email( $item );
			return false;
		}

		// Next up, is this an item we can update?
		if ( 'core' == $type )
			$update = Core_Upgrader::should_update_to_version( $item->current );
		else
			$update = ! empty( $item->autoupdate );

		/**
		 * Filters whether to automatically update core, a plugin, a theme, or a language.
		 *
		 * The dynamic portion of the hook name, `$type`, refers to the type of update
		 * being checked. Can be 'core', 'theme', 'plugin', or 'translation'.
		 *
		 * Generally speaking, plugins, themes, and major core versions are not updated
		 * by default, while translations and minor, patch, and nightly versions for core are
		 * updated by default.
		 *
		 * See the
		 * {@see 'allow_dev_auto_core_updates'},
		 * {@see 'allow_nightly_auto_core_updates'},
		 * {@see 'allow_minor_auto_core_updates'}, and
		 * {@see 'allow_major_auto_core_updates'}
		 * filters for a more straightforward way to adjust core updates.
		 *
		 * @since 1.0.0 Added filter for ClassicPress nightly updates.
		 * @since WP-3.7.0
		 *
		 * @param bool   $update Whether to update.
		 * @param object $item   The update offer.
		 */
		$update = apply_filters( "auto_update_{$type}", $update, $item );

		if ( ! $update ) {
			if ( 'core' == $type )
				$this->send_core_update_notification_email( $item );
			return false;
		}

		// If it's a core update, are we actually compatible with its requirements?
		if ( 'core' == $type ) {
			global $wpdb;

			$php_compat = version_compare( phpversion(), $item->php_version, '>=' );
			if ( file_exists( WP_CONTENT_DIR . '/db.php' ) && empty( $wpdb->is_mysql ) )
				$mysql_compat = true;
			else
				$mysql_compat = version_compare( $wpdb->db_version(), $item->mysql_version, '>=' );

			if ( ! $php_compat || ! $mysql_compat )
				return false;
		}

		return true;
	}