# Azure Service Bus Transport (Legacy) Upgrade Version 8 to 9



## .NET Framework 4.6 required

Azure Service Bus Transport version 9 depends on Azure Service Bus client version 5 which requires .NET Framework 4.6.


## Client-side batching (flush interval) aligned with Microsoft Azure Service Bus client default

The default value for client-side batching configured using `BatchFlushInterval(TimeSpan)` API has changed from 0.5 sec to 20 ms to align better with the Azure Service Bus client [default value](https://learn.microsoft.com/en-us/dotnet/api/microsoft.servicebus.messaging.messagesender.batchflushinterval).