---
title: "Important: #110653 - Unidirectional MM relations are copied during localization"
manual: "TYPO3 Core Changelog"
version: "main"
permalink: "https://docs.typo3.org/permalink/changelog:important-110653-1789496364"
source: "Changelog/14.3.x/Important-110653-CopyUnidirectionalMmRelationsOnLocalization.rst"
typo3-version: "14.3.x"
typo3-major: 14
type: "important"
issue: 110653
forge: "https://forge.typo3.org/issues/110653"
tags: ["TCA", "ext:core"]
rendered: "2026-10-27T20:58:30+00:00"
---

# Important: #110653 - Unidirectional MM relations are copied during localization {#important-110653-1789496364}

See [forge#110653](https://forge.typo3.org/issues/110653)

## Description {#description}

When a translatable record with a unidirectional many-to-many relation is
localized, the relation is now copied to the translated record.

Previously, every MM field without `MM_opposite_field` was considered the
local side of a bidirectional relation. This also matched unidirectional MM
fields and caused their relations to be omitted during localization.

TYPO3 now omits relations only when the field declares
`MM_oppositeUsage` or another field points back to it through
`MM_opposite_field`.

## Affected installations {#affected-installations}

Installations with translatable records that use unidirectional MM fields are
affected.

## Migration {#migration}

No configuration change is required. Relations already omitted from existing
translations must be restored manually.