---
title: "Breaking: #82296 - Removed constant TYPO3_user_agent"
manual: "TYPO3 Core Changelog"
version: "main"
permalink: "https://docs.typo3.org/permalink/changelog:breaking-82296"
source: "Changelog/9.0/Breaking-82296-UserAgentConstantRemoved.rst"
typo3-version: "9.0"
typo3-major: 9
type: "breaking"
issue: 82296
forge: "https://forge.typo3.org/issues/82296"
tags: ["PHP-API", "FullyScanned"]
rendered: "2026-09-17T12:41:04+00:00"
---

# Breaking: #82296 - Removed constant TYPO3_user_agent {#breaking-82296-removed-constant-typo3-user-agent}

See [forge#82296](https://forge.typo3.org/issues/82296)

## Description {#description}

The unused PHP constant `TYPO3_user_agent` containing information of the User Agent string sent
for requests by TYPO3, has been removed.

## Impact {#impact}

Calling the constant will result in a PHP fatal error.

## Affected Installations {#affected-installations}

TYPO3 installations with third-party extensions that make use of the PHP constant.

## Migration {#migration}

The extension scanner checks if the constant is used.

Any extension authors are encouraged to use php:`$GLOBALS['TYPO3_CONF_VARS']['HTTP']['headers']['User-Agent']`
instead.