Upgrading a standard instance to a local disk-based cluster instance does not require any code modifications. This is because proxy nodes can handle architecture changes seamlessly, allowing you to use the cluster architecture in the same way as you use the standard architecture.
If your business requirements outgrow the capabilities of a standard instance, you can migrate the data of the standard instance to a cluster instance that has proxy nodes without having to modify the code. This significantly reduces your costs.
Proxy nodes can balance loads, route commands, manage the traffic to read replicas, cache hotkey data, and support multi-database usage within a cluster instance. For more information, see Features of proxy nodes.
If you want to upgrade a standard instance to a cloud disk-based cluster instance, you must modify the code based on the SDK that you use.