---
title: "Important: #105175 - Move FrontendBackendUserAuthentication into EXT:frontend"
manual: "TYPO3 Core Changelog"
version: "main"
permalink: "https://docs.typo3.org/permalink/changelog:important-105175-1727799093"
source: "Changelog/13.4/Important-105175-MoveFrontendBackendUserAuthenticationIntoEXTfrontend.rst"
typo3-version: "13.4"
typo3-major: 13
type: "important"
issue: 105175
forge: "https://forge.typo3.org/issues/105175"
tags: ["Frontend", "ext:frontend"]
rendered: "2026-09-20T18:31:11+00:00"
---

# Important: #105175 - Move FrontendBackendUserAuthentication into EXT:frontend {#important-105175-1727799093}

See [forge#105175](https://forge.typo3.org/issues/105175)

## Description {#description}

The internal `\TYPO3\CMS\Frontend\Authentication\FrontendBackendUserAuthentication`
class, used for frontend requests while being logged in the backend has been
moved from EXT:backend to EXT:frontend, since its dependencies are limited
to EXT:core and EXT:frontend.

While for v13 a class alias mapping and a legacy notation for IDE's is
available, the class is marked as `@internal` and therefore does not fall
under TYPO3's Core API deprecation policy.