---
title: "Addon update mode enum"
url: "https://help.internetx.com/en/api/core-addon-update-mode-enum/"
lang: "en"
section: "API reference — API reference (XML/JSON)"
breadcrumb: "API documentation (JSON/XML) > Enums and constants"
updated: "2023-09-26"
---

# Addon update mode enum

## Description

You use this keyword to influence how the additional specifications (extensions) are handled during the update. Only possible for _ContactUpdate_ and _DomainUpdate_.

## Possible values

-   REPLACE = existing data is replaced
-   MERGE = existing data is supplemented

Default is MERGE.