> For the complete documentation index, see [llms.txt](https://docs.coherence.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.coherence.io/2.3/support/upgrading-unity-sdk/upgrade-1.8-greater-than-2.0.md).

# Upgrade 2.0 -> 2.1

## <mark style="color:yellow;">Deleted:</mark> UDPTransport

Starting from 2.1, the original UDPTransport is gone and replaced with an alloc-less\* UDP transport layer called UdpTransportV2.

The [Steam Sample](https://github.com/coherence/steam-integration-sample) has been updated to use the UdpTransportV2 for the header size information.

{% hint style="warning" %}
\* Unity's sockets implementation for UDP is not alloc-less so there are still small allocations when sending data that is out of our control.
{% endhint %}

## <mark style="color:yellow;">Deleted:</mark> TransportConfiguration

Starting from 2.1, the TransportConfiguration is no longer a required paramter for the CoherenceBridge, Client or IClient interface's SetTransport method.

This property has also been removed from the RuntimeSettings along with DefaultTransportMode which was made obsolete in a previous update.

## <mark style="color:yellow;">Deleted:</mark> ITransport::PrepareDisconnect()

In the examples for setting up a custom transport this was recommended to override to send messages before closing the transport. It is no longer required.


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