---
title: "Upgrade from legacy Voice4Teams"
canonical: "https://help.callroute.com/space/CKB/2633465862/Upgrade%20from%20legacy%20Voice4Teams"
format: markdown
---
If your organisation currently uses the legacy **Voice4Teams** service, upgrading to the new **Callroute-powered Voice4Teams service** takes place automatically after you authorise Microsoft 365 from the **8x8 Admin Console**.

The upgrade is designed to require no further customer action once Microsoft 365 authorisation has been completed.

## How the upgrade works

### 1. Authorise Microsoft 365

The upgrade process starts when you complete the Microsoft 365 authorisation from the 8x8 Admin Console.

This establishes the connection required for Callroute to configure Voice4Teams in your Microsoft 365 tenant.

### 2. Callroute synchronises Microsoft 365

Callroute automatically retrieves the Microsoft 365 information required for the upgrade.

There is no requirement to sign in to Callroute or manually start a synchronisation.

### 3. Existing Voice4Teams users are identified

Callroute automatically identifies and validates the existing **legacy Voice4Teams users** before the upgrade.

Information supplied by 8x8 is compared with recently synchronised Microsoft 365 information to ensure the users and telephone numbers required for the upgrade can be correctly identified.

This validation takes place automatically as part of the upgrade workflow.

### 4. Upgrade starts automatically

Once the required identification and validation checks have completed successfully, the upgrade automatically follows.

The upgrade is performed as a **whole-tenant cutover**. All existing legacy Voice4Teams users within the tenant are moved together.

Partial upgrades, where some users remain operating through legacy Voice4Teams while others operate through Callroute Voice4Teams, are not supported.

During the upgrade, Callroute:

- applies the required Callroute Voice4Teams routing configuration in Microsoft Teams;
- applies the appropriate Voice4Teams calling policies; and
- enables the Callroute connection to the users' 8x8 service.

Your **8x8 PBX remains the underlying telephony platform**.

## Legacy Voice4Teams registration

Once the upgrade has completed successfully, registration through the legacy Voice4Teams service is disabled.

This prevents the legacy service and Callroute from simultaneously presenting calls to upgraded users.

The legacy configuration is retained during the initial stage of the upgrade process so that the service can be rolled back if required.

## Rollback

If a significant issue is identified during the upgrade, the service can be rolled back.

The retained legacy configuration allows the legacy Voice4Teams registration capability to be restored as part of the rollback process.

Rollback is coordinated by **8x8** and does not require the customer to manually reconfigure individual Voice4Teams users.

## Access to Callroute

You do not need a Callroute administrator account to complete the upgrade.

For the initial Voice4Teams rollout, administrator access to Callroute is provided **after the upgrade has completed**.

Once invited, administrators can use Callroute to view and manage the new Voice4Teams service.

See **[Access Callroute](https://callroute.atlassian.net/wiki/spaces/CKB/pages/2632286214)** for more information.

## After the Upgrade

Once the upgrade is complete, normal Voice4Teams provisioning and service changes originate from **8x8**.

New users subsequently added to Voice4Teams do not go through the legacy upgrade process. Callroute processes them as part of normal Voice4Teams provisioning.

See **[Manage Voice4Teams](https://callroute.atlassian.net/wiki/spaces/CKB/pages/2632515603)** for information about administering the service after upgrade.