Update

curl --request PUT \
  --url https://api.incident.io/v2/follow_ups/{id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "assignee_id": "01FCNDV6P870EA6S7TK1DSYDG0",
  "assignee_team_id": "01FCNDV6P870EA6S7TK1DSYDG0",
  "description": "Call the fire brigade",
  "follow_up_category_id": "01GNW4BAQ7XRMFF6FHKNXDFPRW",
  "follow_up_priority_option_id": "01GNW4BAQ7XRMFF6FHKNXDFPRW",
  "labels": [
    "bug",
    "urgent"
  ],
  "status": "outstanding",
  "title": "Add alerting on replica lag"
}
'

import requests

url = "https://api.incident.io/v2/follow_ups/{id}"

payload = {
    "assignee_id": "01FCNDV6P870EA6S7TK1DSYDG0",
    "assignee_team_id": "01FCNDV6P870EA6S7TK1DSYDG0",
    "description": "Call the fire brigade",
    "follow_up_category_id": "01GNW4BAQ7XRMFF6FHKNXDFPRW",
    "follow_up_priority_option_id": "01GNW4BAQ7XRMFF6FHKNXDFPRW",
    "labels": ["bug", "urgent"],
    "status": "outstanding",
    "title": "Add alerting on replica lag"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.put(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'PUT',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    assignee_id: '01FCNDV6P870EA6S7TK1DSYDG0',
    assignee_team_id: '01FCNDV6P870EA6S7TK1DSYDG0',
    description: 'Call the fire brigade',
    follow_up_category_id: '01GNW4BAQ7XRMFF6FHKNXDFPRW',
    follow_up_priority_option_id: '01GNW4BAQ7XRMFF6FHKNXDFPRW',
    labels: ['bug', 'urgent'],
    status: 'outstanding',
    title: 'Add alerting on replica lag'
  })
};

fetch('https://api.incident.io/v2/follow_ups/{id}', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.incident.io/v2/follow_ups/{id}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PUT",
  CURLOPT_POSTFIELDS => json_encode([
    'assignee_id' => '01FCNDV6P870EA6S7TK1DSYDG0',
    'assignee_team_id' => '01FCNDV6P870EA6S7TK1DSYDG0',
    'description' => 'Call the fire brigade',
    'follow_up_category_id' => '01GNW4BAQ7XRMFF6FHKNXDFPRW',
    'follow_up_priority_option_id' => '01GNW4BAQ7XRMFF6FHKNXDFPRW',
    'labels' => [
        'bug',
        'urgent'
    ],
    'status' => 'outstanding',
    'title' => 'Add alerting on replica lag'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.incident.io/v2/follow_ups/{id}"

	payload := strings.NewReader("{\n  \"assignee_id\": \"01FCNDV6P870EA6S7TK1DSYDG0\",\n  \"assignee_team_id\": \"01FCNDV6P870EA6S7TK1DSYDG0\",\n  \"description\": \"Call the fire brigade\",\n  \"follow_up_category_id\": \"01GNW4BAQ7XRMFF6FHKNXDFPRW\",\n  \"follow_up_priority_option_id\": \"01GNW4BAQ7XRMFF6FHKNXDFPRW\",\n  \"labels\": [\n    \"bug\",\n    \"urgent\"\n  ],\n  \"status\": \"outstanding\",\n  \"title\": \"Add alerting on replica lag\"\n}")

	req, _ := http.NewRequest("PUT", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.put("https://api.incident.io/v2/follow_ups/{id}")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"assignee_id\": \"01FCNDV6P870EA6S7TK1DSYDG0\",\n  \"assignee_team_id\": \"01FCNDV6P870EA6S7TK1DSYDG0\",\n  \"description\": \"Call the fire brigade\",\n  \"follow_up_category_id\": \"01GNW4BAQ7XRMFF6FHKNXDFPRW\",\n  \"follow_up_priority_option_id\": \"01GNW4BAQ7XRMFF6FHKNXDFPRW\",\n  \"labels\": [\n    \"bug\",\n    \"urgent\"\n  ],\n  \"status\": \"outstanding\",\n  \"title\": \"Add alerting on replica lag\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.incident.io/v2/follow_ups/{id}")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Put.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"assignee_id\": \"01FCNDV6P870EA6S7TK1DSYDG0\",\n  \"assignee_team_id\": \"01FCNDV6P870EA6S7TK1DSYDG0\",\n  \"description\": \"Call the fire brigade\",\n  \"follow_up_category_id\": \"01GNW4BAQ7XRMFF6FHKNXDFPRW\",\n  \"follow_up_priority_option_id\": \"01GNW4BAQ7XRMFF6FHKNXDFPRW\",\n  \"labels\": [\n    \"bug\",\n    \"urgent\"\n  ],\n  \"status\": \"outstanding\",\n  \"title\": \"Add alerting on replica lag\"\n}"

response = http.request(request)
puts response.read_body

{
  "follow_up": {
    "assignee": {
      "email": "lisa@incident.io",
      "id": "01FCNDV6P870EA6S7TK1DSYDG0",
      "name": "Lisa Karlin Curtis",
      "role": "owner",
      "slack_user_id": "U02AYNF2XJM"
    },
    "assignee_team": {
      "id": "abc123",
      "name": "abc123"
    },
    "completed_at": "2021-08-17T13:28:57.801578Z",
    "created_at": "2021-08-17T13:28:57.801578Z",
    "creator": {
      "alert": {
        "id": "01GW2G3V0S59R238FAHPDS1R66",
        "title": "*errors.withMessage: PG::Error failed to connect"
      },
      "api_key": {
        "id": "01FCNDV6P870EA6S7TK1DSYDG0",
        "name": "My test API key"
      },
      "user": {
        "email": "lisa@incident.io",
        "id": "01FCNDV6P870EA6S7TK1DSYDG0",
        "name": "Lisa Karlin Curtis",
        "role": "owner",
        "slack_user_id": "U02AYNF2XJM"
      },
      "workflow": {
        "id": "01FCNDV6P870EA6S7TK1DSYDG0",
        "name": "My little workflow"
      }
    },
    "description": "Call the fire brigade",
    "external_issue_reference": {
      "issue_name": "INC-123",
      "issue_permalink": "https://linear.app/incident-io/issue/INC-1609/find-copywriter-to-write-up",
      "provider": "asana"
    },
    "id": "01FCNDV6P870EA6S7TK1DSYDG0",
    "incident_id": "01FCNDV6P870EA6S7TK1DSYDG0",
    "labels": [
      "bug",
      "urgent"
    ],
    "priority": {
      "description": "A follow-up that requires immediate attention.",
      "id": "01GNW4BAQ7XRMFF6FHKNXDFPRW",
      "name": "Urgent",
      "rank": 10
    },
    "status": "outstanding",
    "title": "Cat is stuck in the tree",
    "updated_at": "2021-08-17T13:28:57.801578Z"
  }
}