BP_Admin_Setting_tab

class BP_Admin_Setting_tab extends BP_Admin_Tab {
	public $global_tabs_var = 'bp_admin_setting_tabs';
	public $menu_page       = 'bp-settings';

	public function settings_save() {
		parent::settings_save();
		$this->settings_save_lagecy();
	}

	public function settings_saved() {
		bp_core_redirect( bp_core_admin_setting_url( $this->tab_name, [ 'updated' => 'true' ] ) );
	}

	public function get_active_tab() {
		return bp_core_get_admin_active_tab();
	}

	public function is_tab_visible() {
		return $this->has_fields();
	}

	protected function settings_save_lagecy() {
		global $wp_settings_fields;

		$fields = isset( $wp_settings_fields[ $this->tab_name ] )? (array) $wp_settings_fields[ $this->tab_name ] : [];
		$legacy_names = [];

		foreach( $fields as $section => $settings ) {
			foreach( $settings as $setting_name => $setting ) {
				$legacy_names[] = $setting_name;
			}
		}

		// Some legacy options are not registered with the Settings API, or are reversed in the UI.
		$legacy_options = array(
			'bp-enable-private-network',
			'bp-disable-account-deletion',
			'bp-disable-avatar-uploads',
			'bp-disable-cover-image-uploads',
			'bp-disable-group-avatar-uploads',
			'bp-disable-group-cover-image-uploads',
			'bp_disable_blogforum_comments',
			'bp-disable-profile-sync',
			'bp_restrict_group_creation',
			'hide-loggedout-adminbar',
		);

		$legacy_options = array_intersect( $legacy_options, $legacy_names );

		foreach( $legacy_options as $legacy_option ) {
			// Note: Each of these options is represented by its opposite in the UI
			// Ie, the Profile Syncing option reads "Enable Sync", so when it's checked,
			// the corresponding option should be unset.
			$value = isset( $_POST[$legacy_option] ) ? '' : 1;
			bp_update_option( $legacy_option, $value );
		}
	}
}