Source Reference:

• Component: bbPress :: bbp-core

  File: /bbp-includes/bbp-core-options.php :: Trac Source Line: 258

   *
   * @since bbPress (r2658)
   *
   * @param $default bool Optional.Default value
   *
   * @uses get_option() To get the subscriptions option
   * @return bool Is subscription enabled or not
   */
  function bbp_is_subscriptions_active( $default = true ) {
  	return apply_filters( 'bbp_is_subscriptions_active', (bool) get_option( '_bbp_enable_subscriptions', $default ) );
  }
  
  /**
   * Are topic and reply revisions allowed
   *
   * @since bbPress (r3412)
   *
   * @param $default bool Optional. Default value
   *
   * @uses get_option() To get the allow revisions