# Upgrade Prerequisites

Uninstall any previous version of Atlas Copco Data Communication before upgrading to version 3.7.x or above.

In order to use Atlas Copco Data Communication Unify Service, a valid Atlas Copco Data Communication Unify License must be applied.

RabbitMQ must be configured to use version 2 (v2) of the queues before starting the Atlas Copco Data Communication service.

When upgrading or installing the latest , make sure RabbitMQ prerequisites are set before starting. If these were already set in the previous version, you can skip the steps below.

When using Atlas Copco Data Communication version 3.7.x or above, upgrading from RabbitMQ v3.11.x to RabbitMQ v4.x.x, specific upgrade steps must be followed. Read RabbitMQ v4.2.4 - Upgrade from ACDC 3.7.x for more information.

## RabbitMQ

When upgrading Atlas Copco Data Communication from a version earlier than 3.5.0, configure the following RabbitMQ prerequisites before you upgrade. These steps are not required if you are migrating to RabbitMQ 4.x.x.

1. Ensure all non-meta data queues on the ACDC-Internal virtual host are empty.

2. Stop the RabbitMQ service and navigate to the RabbitMQ folder. The default path is C:\Users\{username}\AppData\Roaming\RabbitMQ. Adjust the path if you have a custom installation.

3. Locate or create the configuration file for RabbitMQ: rabbitmq.conf.

4. Add the following configuration setting to the file.

   `# Set the default version for classic queues`

   `classic_queue.default_version = 2`

   `# Use '2' for classic queues (v2)`

5. Restart the RabbitMQ service.

6. Apply a policy to the ACDC-InternalServices virtual host to ensure its queues run exclusively on version 1 (v1):

   1. Open the Admin tab in RabbitMQ.

   2. Select Policies.

   3. Add or update a policy using the following settings:

      - Virtual host: ACDC-InternalServices

      - Name: v1policy

      - Apply to: Queues

      - Definition: queue-version = 1

7. Delete all queues for the controllers on the ACDC-Internal virtual host before starting the Atlas Copco Data Communication service.