Deprecation: #88559 - $TSFE->sys_language_isocode

See Issue #88559

Description

The public property TypoScriptFrontendController->sys_language_isocode has set the equivalent of TYPO3\CMS\Core\Site\Entity\SiteLanguage->getTwoLetterIsoCode() since the introduction of Site Handling in TYPO3 v9.

As all code should switch to Site Handling, this property can be accessed via the current site language as well, making this property obsolete.

The property has been marked as deprecated.

Impact

Setting or fetching this property will trigger a PHP E_USER_DEPRECATED error.

Affected Installations

Any TYPO3 installation with a third party extension accessing this property, or via TypoScript TSFE:sys_language_isocode.

Migration

Access the property via SiteLanguage->getTwoLetterIsoCode() and sitelanguage:twoLetterIsoCode instead.