# Breaking Changes

{% hint style="info" %}
These following changes were already present in 5.5 and are listed here for visibility.
{% endhint %}

## Service Bus for Windows (for pre 5.5 installations)

Support for Service Bus for Windows Server is removed, when updating to 5.5+ switching to RabbitMQ for full on-premise deployments is mandatory. This also means that using the Service Bus Trigger no longer works with Service Bus for Windows Server.

## ​Remote Subprocesses (for pre 5.5 installations)

Because of changes to the message busses used by Frends, Agent groups within an Environment should be reinstalled at the same time. This is required when Remote Subprocesses are being used.

## ​Frends.Tasks.Attributes support to be removed

Frends Tasks Attributes was a way of modifying the Parameter editor for Tasks before Frends 4.5.6, when it was deprecated and support for it was removed in 5.5.3. Previously imported Tasks will continue to work normally, but new Task imports will require migration to System.ComponentModel.Annotation to support conditional parameter displays etc.

[Check here for more information about Custom Tasks](/guides/development/creating-custom-tasks.md).

## SQL Server requirements

The minimum supported version of SQL Server is now MS SQL Server 2017 for on-premise deployments.


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