Migration Tool¶

Overview¶

Watchtower includes a notify-upgrade command to help convert legacy notification configurations to Shoutrrr URLs for use with the NOTIFICATION URL.

It parses legacy Watchtower notification configurations and outputs Shoutrrr URLs to a temporary file inside the Watchtower container.

Usage¶

The notify-upgrade command converts legacy Watchtower notification configurations into Shoutrrr URLs and writes them to a temporary file inside the container.

Running the Command¶

The notify-upgrade can be run either against a Watchtower container that is already running or as a single-run instance that allows you to convert a Docker Compose configuration or Docker CLI flag / environment variable configuration.

Existing Deployment¶

If Watchtower is already deployed and running with your legacy notification configuration, you can execute notify-upgrade directly inside the container:

docker exec watchtower /watchtower notify-upgrade

This works because the Watchtower binary is installed at /watchtower and notify-upgrade is a built-in subcommand. The common mistake is running docker exec watchtower notify-upgrade, which fails because notify-upgrade is not a standalone executable in $PATH.

Note

Running notify-upgrade inside an existing container does not stop or restart the main Watchtower process. docker exec runs a separate, short-lived process. The only side effect is that the notify-upgrade process will stay alive for up to 5 minutes while waiting for you to retrieve the temporary file, after which it cleans up and exits.

Single-Use Run¶

If you have not yet deployed Watchtower or if you want to run notify-upgrade as a one-off command without starting the persistent Watchtower update loop, then run a temporary container configured with notify-upgrade as the command.

Email (SMTP)GotifySlackMicrosoft Teams

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
  watchtower:
    image: ghcr.io/sidneyojr/watchtower:latest
    command: notify-upgrade
    environment:
      WATCHTOWER_NOTIFICATIONS: email
      WATCHTOWER_NOTIFICATION_EMAIL_SERVER: smtp.example.com
      WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT: 587
      WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER: user@example.com
      WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD: secret
      WATCHTOWER_NOTIFICATION_EMAIL_FROM: sender@example.com
      WATCHTOWER_NOTIFICATION_EMAIL_TO: recipient@example.com
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

docker run --rm \
  --name watchtower-notify-upgrade \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=email \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER=smtp.example.com \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT=587 \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER=user@example.com \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD=secret \
  -e WATCHTOWER_NOTIFICATION_EMAIL_FROM=sender@example.com \
  -e WATCHTOWER_NOTIFICATION_EMAIL_TO=recipient@example.com \
  ghcr.io/sidneyojr/watchtower \
  notify-upgrade

docker run --rm \
  --name watchtower-notify-upgrade \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  notify-upgrade \
  --notifications email \
  --notification-email-server smtp.example.com \
  --notification-email-server-port 587 \
  --notification-email-server-user user@example.com \
  --notification-email-server-password secret \
  --notification-email-from sender@example.com \
  --notification-email-to recipient@example.com

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
  watchtower:
    image: ghcr.io/sidneyojr/watchtower:latest
    command: notify-upgrade
    environment:
      WATCHTOWER_NOTIFICATIONS: gotify
      WATCHTOWER_NOTIFICATION_GOTIFY_URL: "https://my.gotify.tld/"
      WATCHTOWER_NOTIFICATION_GOTIFY_TOKEN: "SuperSecretToken"
      WATCHTOWER_NOTIFICATION_GOTIFY_TLS_SKIP_VERIFY: true
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

docker run --rm \
  --name watchtower-notify-upgrade \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=gotify \
  -e WATCHTOWER_NOTIFICATION_GOTIFY_URL="https://my.gotify.tld/" \
  -e WATCHTOWER_NOTIFICATION_GOTIFY_TOKEN="SuperSecretToken" \
  -e WATCHTOWER_NOTIFICATION_GOTIFY_TLS_SKIP_VERIFY=true \
  ghcr.io/sidneyojr/watchtower \
  notify-upgrade

docker run --rm \
  --name watchtower-notify-upgrade \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  notify-upgrade \
  --notifications gotify \
  --notification-gotify-url "https://my.gotify.tld/" \
  --notification-gotify-token "SuperSecretToken" \
  --notification-gotify-tls-skip-verify

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
  watchtower:
    image: ghcr.io/sidneyojr/watchtower:latest
    command: notify-upgrade
    environment:
      WATCHTOWER_NOTIFICATIONS: slack
      WATCHTOWER_NOTIFICATION_SLACK_HOOK_URL: "https://hooks.slack.com/services/AAA/BBB/CCC"
      WATCHTOWER_NOTIFICATION_SLACK_IDENTIFIER: watchtower-server-1
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

docker run --rm \
  --name watchtower-notify-upgrade \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=slack \
  -e WATCHTOWER_NOTIFICATION_SLACK_HOOK_URL="https://hooks.slack.com/services/AAA/BBB/CCC" \
  -e WATCHTOWER_NOTIFICATION_SLACK_IDENTIFIER=watchtower-server-1 \
  ghcr.io/sidneyojr/watchtower \
  notify-upgrade

docker run --rm \
  --name watchtower-notify-upgrade \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  notify-upgrade \
  --notifications slack \
  --notification-slack-hook-url "https://hooks.slack.com/services/AAA/BBB/CCC" \
  --notification-slack-identifier watchtower-server-1 \

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
  watchtower:
    image: ghcr.io/sidneyojr/watchtower:latest
    command: notify-upgrade
    environment:
      WATCHTOWER_NOTIFICATIONS: msteams
      WATCHTOWER_NOTIFICATION_MSTEAMS_HOOK_URL: "https://prod-00.westus.logic.azure.com:443/workflows/abc123/triggers/manual/paths/invoke?api-version=2016-06-00&sp=/triggers/manual/run&sv=1.0&sig=XXXXXXXX"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

docker run --rm \
  --name watchtower-notify-upgrade \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=msteams \
  -e WATCHTOWER_NOTIFICATION_MSTEAMS_HOOK_URL="https://prod-00.westus.logic.azure.com:443/workflows/abc123/triggers/manual/paths/invoke?api-version=2016-06-00&sp=/triggers/manual/run&sv=1.0&sig=XXXXXXXX" \
  ghcr.io/sidneyojr/watchtower \
  notify-upgrade

docker run --rm \
  --name watchtower-notify-upgrade \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  notify-upgrade \
  --notifications msteams \
  --notification-msteams-hook "https://prod-00.westus.logic.azure.com:443/workflows/abc123/triggers/manual/paths/invoke?api-version=2016-06-00&sp=/triggers/manual/run&sv=1.0&sig=XXXXXXXX"

Important

Replace the example environment variables with your own legacy notification configuration. The notify-upgrade command inspects the container's current configuration, so it must be started with your legacy notification settings.

Retrieving the Generated File¶

After running notify-upgrade, the converted Shoutrrr URL is written to a temporary file in the container's working directory, with a filename like watchtower-notif-urls-XXXXXX.

The command logs the exact container path and prints a copy command, for example:

INFO To get the environment file, use: docker cp abc123:watchtower-notif-urls-123456789 ./watchtower-notifications.env

Copy it to your local machine with:

docker cp <CONTAINER>:<FILE_PATH> ./watchtower-notifications.env

The temporary file is automatically removed after 5 minutes or when the container stops, so copy it promptly after generation. If you are running notify-upgrade as a one-off command (docker run --rm ...), the process will wait up to 5 minutes before exiting.

Migration Walkthrough¶

Select the tab that matches your legacy notification service.

Email (SMTP)GotifySlackMicrosoft Teams

Run the following Docker Compose configuration / Docker CLI command:

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
    watchtower:
        image: ghcr.io/sidneyojr/watchtower:latest
        environment:
            WATCHTOWER_NOTIFICATIONS: email
            WATCHTOWER_NOTIFICATION_EMAIL_SERVER: smtp.example.com
            WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT: 587
            WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER: user@example.com
            WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD: secret
            WATCHTOWER_NOTIFICATION_EMAIL_FROM: sender@example.com
            WATCHTOWER_NOTIFICATION_EMAIL_TO: recipient@example.com
        volumes:
        - /var/run/docker.sock:/var/run/docker.sock

docker run -d \
--name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=email \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER=smtp.example.com \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT=587 \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER=user@example.com \
  -e WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD=secret \
  -e WATCHTOWER_NOTIFICATION_EMAIL_FROM=sender@example.com \
  -e WATCHTOWER_NOTIFICATION_EMAIL_TO=recipient@example.com \
  ghcr.io/sidneyojr/watchtower

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  --notifications email \
  --notification-email-server smtp.example.com \
  --notification-email-server-port 587 \
  --notification-email-server-user user@example.com \
  --notification-email-server-password secret \
  --notification-email-from sender@example.com \
  --notification-email-to recipient@example.com

With the container running, execute the notify-upgrade command:

docker exec watchtower /watchtower notify-upgrade

Then copy the resulting file out of the container:

docker cp <CONTAINER>:<FILE_PATH> ./watchtower-notifications.env

The following converted Shoutrrr URL should be produced:

smtp://user@example.com:secret@smtp.example.com:587/?fromaddress=sender@example.com&toaddresses=recipient@example.com&encryption=ExplicitTLS&usestarttls=yes

Replace the deprecated configuration with the coverted Shoutrrr URL:

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
    watchtower:
        image: ghcr.io/sidneyojr/watchtower:latest
        environment:
            WATCHTOWER_NOTIFICATION_URL: smtp://user@example.com:secret@smtp.example.com:587/?fromaddress=sender@example.com&toaddresses=recipient@example.com&encryption=ExplicitTLS&usestarttls=yes
            WATCHTOWER_NOTIFICATIONS_DELAY: "10"
            WATCHTOWER_NOTIFICATION_TITLE_TAG: Watchtower
        volumes:
        - /var/run/docker.sock:/var/run/docker.sock

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e "WATCHTOWER_NOTIFICATION_URL=smtp://user@example.com:secret@smtp.example.com:587/?fromaddress=sender@example.com&toaddresses=recipient@example.com&encryption=ExplicitTLS&usestarttls=yes" \
  -e WATCHTOWER_NOTIFICATIONS_DELAY=10 \
  -e WATCHTOWER_NOTIFICATION_TITLE_TAG=Watchtower \
  ghcr.io/sidneyojr/watchtower

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  --notification-url "smtp://user@example.com:secret@smtp.example.com:587/?fromaddress=sender@example.com&toaddresses=recipient@example.com&encryption=ExplicitTLS&usestarttls=yes" \
  --notifications-delay 10 \
  --notification-title-tag Watchtower

Note

Avoid using unrecognized flags like WATCHTOWER_NOTIFICATION_EMAIL_SERVER_SSL, as they are ignored and may cause confusion.
Use the encryption and usestarttls URL parameters in the smtp:// URL to control TLS behavior rather than deprecated flags.

Run the following Docker Compose configuration / Docker CLI command:

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
    watchtower:
        image: ghcr.io/sidneyojr/watchtower:latest
        environment:
            WATCHTOWER_NOTIFICATIONS: gotify
            WATCHTOWER_NOTIFICATION_GOTIFY_URL: "https://my.gotify.tld/"
            WATCHTOWER_NOTIFICATION_GOTIFY_TOKEN: "SuperSecretToken"
            WATCHTOWER_NOTIFICATION_GOTIFY_TLS_SKIP_VERIFY: true
        volumes:
        - /var/run/docker.sock:/var/run/docker.sock

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=gotify \
  -e WATCHTOWER_NOTIFICATION_GOTIFY_URL="https://my.gotify.tld/" \
  -e WATCHTOWER_NOTIFICATION_GOTIFY_TOKEN="SuperSecretToken" \
  -e WATCHTOWER_NOTIFICATION_GOTIFY_TLS_SKIP_VERIFY=true \
  ghcr.io/sidneyojr/watchtower

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  --notifications gotify \
  --notification-gotify-url "https://my.gotify.tld/" \
  --notification-gotify-token "SuperSecretToken" \
  --notification-gotify-tls-skip-verify

With the container running, execute the notify-upgrade command:

docker exec watchtower /watchtower notify-upgrade

Then copy the resulting file out of the container:

docker cp <CONTAINER>:<FILE_PATH> ./watchtower-notifications.env

The following converted Shoutrrr URL should be produced:
```
gotify://my.gotify.tld/SuperSecretToken?title=
```

Replace the deprecated configuration with the coverted Shoutrrr URL:

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
    watchtower:
        image: ghcr.io/sidneyojr/watchtower:latest
        environment:
            WATCHTOWER_NOTIFICATION_URL: "gotify://my.gotify.tld/SuperSecretToken?title="
        volumes:
        - /var/run/docker.sock:/var/run/docker.sock

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATION_URL="gotify://my.gotify.tld/SuperSecretToken?title=" \
  ghcr.io/sidneyojr/watchtower

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  --notification-url "gotify://my.gotify.tld/SuperSecretToken?title="

Run the following Docker Compose configuration / Docker CLI command:
Docker ComposeDocker CLI (Env Vars)
services: watchtower: image: ghcr.io/sidneyojr/watchtower:latest environment: WATCHTOWER_NOTIFICATIONS: slack WATCHTOWER_NOTIFICATION_SLACK_HOOK_URL: "https://hooks.slack.com/services/AAA/BBB/CCC" WATCHTOWER_NOTIFICATION_SLACK_IDENTIFIER: watchtower-server-1 volumes: - /var/run/docker.sock:/var/run/docker.sock
```bash docker run -d \ --name watchtower \ -v /var/run/docker.sock:/var/run/docker.sock \ -e WATCHTOWER_NOTIFICATIONS=slack \
-e WATCHTOWER_NOTIFICATION_SLACK_HOOK_URL="https://hooks.slack.com/services/AAA/BBB/CCC" \ -e WATCHTOWER_NOTIFICATION_SLACK_IDENTIFIER=watchtower-server-1 \ ghcr.io/sidneyojr/watchtower ```

Docker CLI (Flags)

```bash docker run -d \ --name watchtower \ -v /var/run/docker.sock:/var/run/docker.sock \ ghcr.io/sidneyojr/watchtower \ --notifications slack \ --notification-slack-hook-url "https://hooks.slack.com/services/AAA/BBB/CCC" \

--notification-slack-identifier watchtower-server-1 \ ```

With the container running, execute the notify-upgrade command:

docker exec watchtower /watchtower notify-upgrade

Then copy the resulting file out of the container:

docker cp <CONTAINER>:<FILE_PATH> ./watchtower-notifications.env

The following converted Shoutrrr URL should be produced:

slack://hook:AAA-BBB-CCC@webhook?botname=watchtower&color=%23406170

Replace the deprecated configuration with the coverted Shoutrrr URL:

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
    watchtower:
        image: ghcr.io/sidneyojr/watchtower:latest
        environment:
            WATCHTOWER_NOTIFICATION_URL: "slack://hook:AAA-BBB-CCC@webhook?botname=watchtower&color=%23406170"
        volumes:
        - /var/run/docker.sock:/var/run/docker.sock

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATION_URL="slack://hook:AAA-BBB-CCC@webhook?botname=watchtower&color=%23406170" \
  ghcr.io/sidneyojr/watchtower

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  --notification-url "slack://hook:AAA-BBB-CCC@webhook?botname=watchtower&color=%23406170"

Run the following Docker Compose configuration / Docker CLI command:

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
    watchtower:
        image: ghcr.io/sidneyojr/watchtower:latest
        environment:
            WATCHTOWER_NOTIFICATIONS: msteams
            WATCHTOWER_NOTIFICATION_MSTEAMS_HOOK_URL: "https://prod-00.westus.logic.azure.com:443/workflows/abc123/triggers/manual/paths/invoke?api-version=2016-06-00&sp=/triggers/manual/run&sv=1.0&sig=XXXXXXXX"
        volumes:
        - /var/run/docker.sock:/var/run/docker.sock

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=msteams \
  -e WATCHTOWER_NOTIFICATION_MSTEAMS_HOOK_URL="https://prod-00.westus.logic.azure.com:443/workflows/abc123/triggers/manual/paths/invoke?api-version=2016-06-00&sp=/triggers/manual/run&sv=1.0&sig=XXXXXXXX" \
  ghcr.io/sidneyojr/watchtower

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  --notifications msteams \
  --notification-msteams-hook "https://prod-00.westus.logic.azure.com:443/workflows/abc123/triggers/manual/paths/invoke?api-version=2016-06-00&sp=/triggers/manual/run&sv=1.0&sig=XXXXXXXX"

With the container running, execute the notify-upgrade command:

docker exec watchtower /watchtower notify-upgrade

Then copy the resulting file out of the container:

docker cp <CONTAINER>:<FILE_PATH> ./watchtower-notifications.env

The following converted Shoutrrr URL should be produced:

teams://?host=https%3A%2F%2Fprod-00.westus.logic.azure.com%3A443%2Fworkflows%2Fabc123%2Ftriggers%2Fmanual%2Fpaths%2Finvoke%3Fapi-version%3D2016-06-00%26sp%3D%2Ftriggers%2Fmanual%2Frun%26sv%3D1.0%26sig%3DXXXXXXXX&color=%23406170

Replace the deprecated configuration with the coverted Shoutrrr URL:

Docker ComposeDocker CLI (Env Vars)Docker CLI (Flags)

services:
    watchtower:
        image: ghcr.io/sidneyojr/watchtower:latest
        environment:
            WATCHTOWER_NOTIFICATION_URL: "teams://?host=https%3A%2F%2Fprod-00.westus.logic.azure.com%3A443%2Fworkflows%2Fabc123%2Ftriggers%2Fmanual%2Fpaths%2Finvoke%3Fapi-version%3D2016-06-00%26sp%3D%2Ftriggers%2Fmanual%2Frun%26sv%3D1.0%26sig%3DXXXXXXXX&color=%23406170"
        volumes:
        - /var/run/docker.sock:/var/run/docker.sock

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATION_URL="teams://?host=https%3A%2F%2Fprod-00.westus.logic.azure.com%3A443%2Fworkflows%2Fabc123%2Ftriggers%2Fmanual%2Fpaths%2Finvoke%3Fapi-version%3D2016-06-00%26sp%3D%2Ftriggers%2Fmanual%2Frun%26sv%3D1.0%26sig%3DXXXXXXXX&color=%23406170" \
  ghcr.io/sidneyojr/watchtower

docker run -d \
  --name watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  ghcr.io/sidneyojr/watchtower \
  --notification-url "teams://?host=https%3A%2F%2Fprod-00.westus.logic.azure.com%3A443%2Fworkflows%2Fabc123%2Ftriggers%2Fmanual%2Fpaths%2Finvoke%3Fapi-version%3D2016-06-00%26sp%3D%2Ftriggers%2Fmanual%2Frun%26sv%3D1.0%26sig%3DXXXXXXXX&color=%23406170"

Automated Migration Script¶

If you have a docker-compose.yaml with a watchtower service configured for legacy notifications, you can use the script below to run the entire migration process end-to-end. It starts the container, executes notify-upgrade, extracts the generated file, prints its contents, and cleans up.

#!/usr/bin/env bash
set -euo pipefail

SERVICE="${1:-watchtower}"
OUTPUT="${2:-./watchtower-notifications.env}"

CONTAINER=$(docker compose run -d "${SERVICE}" notify-upgrade)

trap 'docker rm -f "${CONTAINER}" >/dev/null 2>&1 || true' EXIT

if ! docker ps -q --filter "id=${CONTAINER}" | grep -q .; then
    echo "notify-upgrade container exited before producing output. Logs:" >&2
    docker logs "${CONTAINER}" >&2 || true

    exit 1
fi

FILE=""
TIMEOUT=300
INTERVAL=2
ELAPSED=0

while [[ ${ELAPSED} -lt ${TIMEOUT} ]]; do
    FILE=$(docker logs "${CONTAINER}" 2>&1 | grep -oE 'watchtower-notif-urls-[^ ]+' | tail -1 || true)

    if [[ -n "${FILE}" ]]; then
        break
    fi

    sleep "${INTERVAL}"

    ELAPSED=$((ELAPSED + INTERVAL))
done

if [[ -z "${FILE}" ]]; then
    echo "Timed out waiting for notify-upgrade output. Logs:" >&2
    docker logs "${CONTAINER}" >/dev/null 2>&1 || true

    exit 1
fi

docker cp "${CONTAINER}:${FILE}" "${OUTPUT}"

echo "=== Generated Shoutrrr URL ==="
cat "${OUTPUT}"

Important

The service must already be defined in docker-compose.yaml with your legacy notification environment variables. The script assumes the service name defaults to watchtower.
The command will self-cleanup after 5 minutes or when the script exits.
Slack channel customization is not preserved by notify-upgrade. The generated URL always uses the default webhook channel. If you need a custom channel, then manually edit the resulting Shoutrrr URL after migration.