> [!CAUTION]
> **Caution:** This documentation covers Edge for Private Cloud 4.19.01, which is no longer supported. Google does not provide security patches, bug fixes, or technical support for this version. The current supported version is 4.54.00. See the [Edge for Private Cloud documentation](https://docs.apigee.com/private-cloud/latest/overview) for the current version, or [All versions](https://docs.apigee.com/private-cloud/versions) to compare releases.

*Edge for Private Cloud v4.19.01*


This section explains how to upgrade [Apigee mTLS](https://docs.apigee.com/private-cloud/v4.50.00/mtls-intro)
to Apigee Edge for Private Cloud v4.19.01.

> [!NOTE]
> Apigee mTLS is supported on Apigee Edge for Private Cloud versions 4.50.00, 4.19.06, and 4.19.01. You cannot use `apigee-mtls` on versions 4.18.\* or lower.

## Before you begin

Apigee recommends that you perform backups of the Cassandra, Postgres, and Zookeeper services
before you upgrade Apigee mTLS.

## Upgrading

**To upgrade Apigee mTLS:**

1. Stop all Apigee components, including `apigee-mtls`, by executing the following command:

   ```
   /opt/apigee/apigee-service/bin/apigee-all stop
   ```
2. Uninstall Apigee mTLS by executing the following command:

   ```
   /opt/apigee/apigee-service/bin/apigee-service apigee-mtls uninstall
   ```
3. Install the newer version of Apigee mTLS by following the [Apigee mTLS installation instructions](https://docs.apigee.com/private-cloud/v4.19.01/mtls-install).
4. Start `apigee-mtls` on all hosts by executing the following command:

   ```
   /opt/apigee/apigee-service/bin/apigee-service apigee-mtls start
   ```
5. Start the remaining Private Cloud components by following the existing [startup sequence documentation](https://docs.apigee.com/private-cloud/v4.19.01/starting-stopping-and-restarting-apigee-edge#start-order).

   > [!NOTE]
   > **Note:** It may take as long as 3-5 minutes for Zookeeper to re-establish its quorum within the mTLS service mesh. This may or may not be of consequence depending on how much---or how little---automation is used during the restart process.

6. Follow the existing [update/upgrading ordering
   steps](https://docs.apigee.com/private-cloud/v4.19.01/update-apigee-edge-4180x-41901#orderofmachineupdate) for other components.