curl -X PUT \
 /dunning/overdue-rules/{id} \
 --header "Content-Type: application/json" \
 --header "Authorization: Bearer <token>" \
 --data '{
    "daysOverdue": "1",
    "dueInDays": "7",
    "emailTemplate": {
        "subject": "Order confirmation #{{ order.number }}",
        "contentHtml": "<h1>Order confirmation<\/h1><p>Thank you for your order.<\/p>"
    },
    "documentTemplate": {
        "title": "Your invoice $invoice.documentId",
        "introduction": "Thank you for your order.",
        "closing": "Pay this invoice in the next 7 days.",
        "information": [
            {
                "key": "Invoice number",
                "value": "$invoice.documentId"
            }
        ]
    },
    "amountInCents": "100",
    "attachOriginalInvoice": "1",
    "sendLetter": "",
    "isEnabled": "1"
}'

import requests

url = "https://coreapi.io/dunning/overdue-rules/{id}"

payload = {
    "daysOverdue": 1,
    "dueInDays": 7,
    "type": "reminder",
    "emailTemplate": {
        "subject": "Order confirmation #{{ order.number }}",
        "contentHtml": "<h1>Order confirmation</h1><p>Thank you for your order.</p>"
    },
    "documentTemplate": {
        "title": "Your invoice $invoice.documentId",
        "introduction": "Thank you for your order.",
        "closing": "Pay this invoice in the next 7 days.",
        "information": [
            {
                "key": "Invoice number",
                "value": "$invoice.documentId"
            }
        ]
    },
    "amountInCents": 100,
    "attachOriginalInvoice": True,
    "sendLetter": True,
    "isEnabled": True
}
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({
    daysOverdue: 1,
    dueInDays: 7,
    type: 'reminder',
    emailTemplate: {
      subject: 'Order confirmation #{{ order.number }}',
      contentHtml: '<h1>Order confirmation</h1><p>Thank you for your order.</p>'
    },
    documentTemplate: {
      title: 'Your invoice $invoice.documentId',
      introduction: 'Thank you for your order.',
      closing: 'Pay this invoice in the next 7 days.',
      information: [{key: 'Invoice number', value: '$invoice.documentId'}]
    },
    amountInCents: 100,
    attachOriginalInvoice: true,
    sendLetter: true,
    isEnabled: true
  })
};

fetch('https://coreapi.io/dunning/overdue-rules/{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://coreapi.io/dunning/overdue-rules/{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([
    'daysOverdue' => 1,
    'dueInDays' => 7,
    'type' => 'reminder',
    'emailTemplate' => [
        'subject' => 'Order confirmation #{{ order.number }}',
        'contentHtml' => '<h1>Order confirmation</h1><p>Thank you for your order.</p>'
    ],
    'documentTemplate' => [
        'title' => 'Your invoice $invoice.documentId',
        'introduction' => 'Thank you for your order.',
        'closing' => 'Pay this invoice in the next 7 days.',
        'information' => [
                [
                                'key' => 'Invoice number',
                                'value' => '$invoice.documentId'
                ]
        ]
    ],
    'amountInCents' => 100,
    'attachOriginalInvoice' => true,
    'sendLetter' => true,
    'isEnabled' => true
  ]),
  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;
}

{
  "level": 1,
  "daysOverdue": 1,
  "dueInDays": 7,
  "type": "reminder",
  "emailTemplate": {
    "name": "Order confirmation",
    "description": "Order confirmation for a new order",
    "subject": "Order confirmation #{{ order.number }}",
    "contentHtml": "<h1>Order confirmation</h1><p>Thank you for your order.</p>",
    "contentPlain": "Order confirmation\\n\\nThank you for your order.",
    "id": "8d6b0c3e-0b7a-4b0a-8b1a-3b0b8b2d0b0b",
    "senderName": "Acme Inc.",
    "senderAddress": "noreply@acme.com",
    "isSystem": true,
    "isEnabled": "true",
    "createdAt": "2021-01-01T00:00:00+00:00",
    "updatedAt": "2021-01-01T00:00:00+00:00",
    "preHeader": "Your order confirmation",
    "versions": [
      {
        "id": "mltplv_1b2nE1a2b3nF4c5d6e7f8g9h0j",
        "version": 1,
        "subject": "Hello {{ name }}",
        "contentHtml": "<h1>Hello {{ name }}</h1>",
        "contentPlain": "Hello {{ name }}",
        "preHeader": "Hello {{ name }}",
        "createdAt": "2021-01-01T00:00:00+00:00",
        "createdBy": "system"
      }
    ],
    "currentVersion": {
      "id": "mltplv_1b2nE1a2b3nF4c5d6e7f8g9h0j",
      "version": 1,
      "subject": "Hello {{ name }}",
      "contentHtml": "<h1>Hello {{ name }}</h1>",
      "contentPlain": "Hello {{ name }}",
      "preHeader": "Hello {{ name }}",
      "createdAt": "2021-01-01T00:00:00+00:00",
      "createdBy": "system"
    }
  },
  "documentTemplate": {
    "type": "invoice",
    "name": "invoice",
    "language": "de",
    "title": "Your invoice $invoice.documentId",
    "introduction": "Thank you for your order.",
    "closing": "Pay this invoice in the next 7 days.",
    "id": "00000000-0000-0000-0000-000000000000",
    "brandColor": "#000000",
    "headerBackgroundColor": "#ffffff",
    "logoPosition": "right",
    "logoUrl": "base64",
    "information": [
      {
        "key": "Invoice number",
        "value": "$invoice.documentId"
      }
    ],
    "footer": [
      {
        "line1": "Company name",
        "line2": "Street",
        "line3": "City",
        "line4": "Country",
        "line5": "VAT number"
      }
    ]
  },
  "id": "ad8f3b1c-4f0e-4b9e-8b0a-0e0e0e0e0e0e",
  "amountInCents": 100,
  "attachOriginalInvoice": true,
  "sendLetter": true,
  "isEnabled": true,
  "createdAt": "2021-01-01T00:00:00+00:00",
  "updatedAt": "2021-01-01T00:00:00+00:00"
}