> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Backward Compatibility

## API Compatibility

As stated in our [Versioning Policy](https://docs.activeviam.com/eos.html), backward compatibility is preserved across all maintenance versions.<br />
A product built on a previous maintenance version can be upgraded without requiring any modifications.

## Compatibility Policy for Nodes in a Cluster

An Atoti application can be [distributed](../distributed/distributed_intro) across multiple nodes, potentially running in separate Java processes.<br />
Atoti does not guarantee backward compatibility between node processes running different versions.<br />
When nodes operate on different versions, communication issues may arise due to changes in internal messaging and data structures.<br />
However, we recognize the importance of smooth upgrades.<br />
Therefore, while backward compatibility is not ensured, we commit to the following:

* Such changes will be rare.
* They will be explicitly documented in the changelog.