https://www.drupal.org/node/1323808
civicrm_activity_ical 6.x-1.x-dev | Drupal.org
Oct 22, 2014 - Development snapshot.
activity ical6 xcivicrm1dev
https://www.drupal.org/node/1484260
civicrm_activity_ical 7.x-1.x-dev | Drupal.org
Jul 6, 2016 - Development snapshot for 7.x branch.
activity ical7 xcivicrm1dev