Hello,

I am trying to update Tasks in Zoho CRM to make them recurring yearly, but I cannot find the correct recurrence pattern or way to update the Recurring_Activity field via API or Deluge.

I have tried:

• Sending a string like "RRULE:FREQ=YEARLY;INTERVAL=1"

• Sending an object like { "RRULE": "FREQ=YEARLY;INTERVAL=1" }

• Adding additional parameters like DTSTART or UNTIL

All attempts return the error:

{
  code: "INVALID_DATA",
  details: {
    expected_data_type: "RRULE",
    api_name: "Recurring_Activity",
    json_path: "$.data[0].Recurring_Activity.RRULE"
  },
  message: "invalid recurrence pattern",
  status: "error"

I want the task to repeat every year on the same day as the Due_Date and never end.

I suspect the issue is either the format of the RRULE string or the way Recurring_Activity must be updated via API, but I cannot find any working example in the documentation.

Can someone provide a working RRULE format for a yearly task recurrence and show how to update it via API or Deluge?

My code example:
void automation.MassUpdateTasks()
{
    tasks = zoho.crm.getRecords("Tasks", 1, 2000);

    for each t in tasks
    {
        taskId = t.get("id");
        dueDate = t.get("Due_Date"); // es. "2035-01-01"

        d = dueDate.toDate("yyyy-MM-dd");
        month = d.getMonth(); // 1..12
        day = d.getDay();     // 1..31

        rruleString = "FREQ=YEARLY;INTERVAL=1;BYMONTH=" + month + ";BYMONTHDAY=" + day;

        updateMap = map();
        updateMap.put("Recurring_Activity", rruleString);

        resp = zoho.crm.updateRecord("Tasks", taskId.toLong(), updateMap);
        info resp;
    }
}

Tried also 
        rruleString = "FREQ=YEARLY;INTERVAL=1;BYMONTH=" + month + ";BYMONTHDAY=" + day + ";DTSTART=" + startDate + ";UNTIL=-1";

Thank you in advance!