Deprecation: #94165 - sys_language table

See forge#94165

Description

Since the introduction of site handling back in TYPO3 v9, available languages and their associated information, for example locale, ISO code or the navigation title are configured in the site configurations. As a consequence, the sys_language table just duplicated this information and is therefore now deprecated.

The Core internally does not longer rely on this table but fetches necessary information from the site languages instead. This means, there won't be any relation to the sys_language table, which allows to define any kind of "ID" for the languageField field of records, which is usually sys_language_uid.

Also the site languages, used in site configurations, are now completely independent of any sys_language record. Previously, when using the site module to create or edit a site configuration, site languages could only be added when a corresponding sys_language record existed. This has now changed. The site configurations' languages field now features a Create new language button, which allows to create a new site language for this site configuration. Such newly created site language will then also be available in the selector box of all other site configurations. The ID for a new site language is always created automatically (auto-increment). When selecting this site language in another site configuration, most of the fields will now be prefilled.

Impact

Currently there is no direct impact. However, if your code relies on TYPO3 processing sys_language, you might have to adapt those places to use site languages instead.

Affected Installations

All installations which rely on TYPO3 processing the sys_language table. For example for fetching available languages and their related information.

Migration

Adapt your code to always use site languages for fetching and processing language related information.

For example, use the new TCA type language, introduced in forge#57082, instead of foreign_table => sys_language for selecting a records' language.