# Azure Service Bus Transport Upgrade Version 2 to 3


## Configuring the Azure Service Bus transport

To use the Azure Service Bus transport for NServiceBus, create a new instance of `AzureServiceBusTransport` and pass it to `EndpointConfiguration.UseTransport`.

Instead of:

```csharp
var transport = endpointConfiguration.UseTransport<AzureServiceBusTransport>();
transport.ConnectionString(connectionString);
```

Use:

```csharp
var transport = new AzureServiceBusTransport(connectionString);
endpointConfiguration.UseTransport(transport);
```

> [!NOTE]
> The existing API surface with `UseTransport<T>()` is supported via a [shim API](https://en.wikipedia.org/wiki/Shim_(computing)) to ease migration. However, it is recommended to switch to the new transport configuration API to prepare for future upgrades of NServiceBus.


## Configuration options

The Azure Service Bus transport configuration options have been moved to the `AzureServiceBusTransport` class. See the following table for further information:

| Version 2 configuration option | Version 3 configuration option
| --- | --- |
| TopicName | TopicName |
| EntityMaximumSize | EntityMaximumSize |
| EnablePartitioning | EnablePartitioning |
| PrefetchMultiplier | PrefetchMultiplier |
| PrefetchCount | PrefetchCount |
| TimeToWaitBeforeTriggeringCircuitBreaker | TimeToWaitBeforeTriggeringCircuitBreaker |
| SubscriptionNameShortener | SubscriptionNamingConvention |
| SubscriptionNamingConvention | SubscriptionNamingConvention |
| RuleNameShortener | SubscriptionRuleNamingConvention |
| SubscriptionRuleNamingConvention | SubscriptionRuleNamingConvention |
| UseWebSockets | UseWebSockets |
| TokenCredential | Overloaded constructor of the transport |
| CustomRetryPolicy | RetryPolicy |

### TokenCredential

Previously when using `CustomTokenCredential` or `TokenCredential` it was required to pass a fully-qualified namespace (e.g. `<asb-namespace-name>.servicebus.windows.net`) instead of a connection string (e.g. `Endpoint=sb://<asb-namespace-name>.servicebus.windows.net>;[...]`). The dual purpose of the connection-string option has been removed. To use `TokenCredential` pass the credential plus the fully-qualified namespace to the constructor of the transport.

<!-- snippet: 2to3-token-credentials -->

```cs
var transportWithTokenCredentials = new AzureServiceBusTransport("[NAMESPACE].servicebus.windows.net", new DefaultAzureCredential());
endpointConfiguration.UseTransport(transportWithTokenCredentials);
```

<!-- endsnippet -->

## Accessing the native incoming message

The Azure.Messaging.ServiceBus client SDK introduces a set of new classes to represent messages. Previously there was only the `Message` class to represent either an incoming message or an outgoing message. With the new client SDK the incoming message type is `ServiceBusReceivedMessage`. If access to the native incoming message is required, make sure the correct type is used. See the [native message customization documentation](/transports/azure-service-bus/native-message-access.md) for further details.

## Native message customization

`IMessageHandlerContext` and `IPipelineContext` no longer need to be passed to the `CustomizeNativeMessage` method. See the [native message customization documentation](/transports/azure-service-bus/native-message-access.md) for further details.

## Auto-lock renewal

The auto-lock renewal is now supported for an extended period of time and can be customized by specifying `MaxAutoLockRenewalDuration`.

<!-- snippet: 2to3-custom-auto-lock-renewal -->

```cs
transport.MaxAutoLockRenewalDuration = TimeSpan.FromMinutes(10);
```

<!-- endsnippet -->

### Transaction timeout

The transport now allows transactions to take longer than the default [`TransactionManager.MaximumTimeout`](https://learn.microsoft.com/en-us/dotnet/api/system.transactions.transactionmanager.maximumtimeout). It is no longer required to override the maximum timeout.

### Advanced/custom lock renewal

Previous versions of the transport did not support extending the message lock past five minutes, though custom code may have attempted to implement this functionality. Custom implementations should be removed and the built-in [lock renewal feature](/transports/azure-service-bus/configuration.md#lock-renewal) should be used instead.