> For the complete documentation index, see [llms.txt](https://help.security.gallagher.com/knowledge-hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.security.gallagher.com/knowledge-hub/products/cc-software/configure/interface-options/api/cardholder-change-tracking-api.md).

# Cardholder change tracking API

Support existing Cardholder Change Tracking API integrations and migrate to REST.

> ⚠️ **Deprecated.** This API is supported but **deprecated in favour of the same functions in the 8.30 REST API**. There is also a formal obsolescence advisory (**C12707 Cardholder Change Tracking API, April 2023**). For new work, use the [REST API](/knowledge-hub/products/cc-software/configure/interface-options/api/representational-state-transfer-rest-api.md) Cardholders edition (C12784). This page is retained for existing-integration support only.

## What it is

A query API that lets a third-party application retrieve **Cardholder properties** from the Command Centre database. It **polls** the database. If a cardholder's properties changed since the previous poll, the query returns the cardholder's current properties.

**DLLs provided:** `CardholderChangeTrackingAPI.dll`, `GGL_CLV.dll`, `Nlog.dll`.

**Command Centre versions supported:** v7.90 – v8.50.

## Use cases (historical)

* Limit duplicate data entry across systems. Enter a cardholder in Command Centre once, then let other systems listen for changes and pull updates into their own databases.
* **"Follow-Me" printing.** The cardholder's card number / CSN (as assigned in Command Centre) is made known to network printers so staff can print and collect documents.
* Command Centre as the **source of truth for cardholder images** shared with other systems (for example a company intranet).

## Migration

Replace with the **REST API Cardholders** edition (C12784), available from the 8.30 REST API onward. See [REST API](/knowledge-hub/products/cc-software/configure/interface-options/api/representational-state-transfer-rest-api.md).


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://help.security.gallagher.com/knowledge-hub/products/cc-software/configure/interface-options/api/cardholder-change-tracking-api.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.