one_shot - a one-time event, which causes by an external object (the value is only valid if the 'date' is not specified) fixed_date - a one-time event, which occurs at a specified 'date' (the value is valid only if the 'date' is given) period_date - reusable event that occurs within a given 'period' from the initial 'date' (the value is only valid if the 'period' specified)

Declare which notification channels could be used to notify user about events. Allowed values: email, apns, gcm, mpns, bbps.

Should contain a string of tags divided by commas. Recipients (users) must have at least one tag that specified in list.