In previous versions of core, Drupal\Core\Language\LanguageManagerInterface::getLanguageSwitchLinks() was documented as returning an array of links, but Drupal\language\ConfigurableLanguageManager::getLanguageSwitchLinks() in fact returned an object containing an array of links, or FALSE if there were no switch links.
Drupal\Core\Language\LanguageManagerInterface::getLanguageSwitchLinks() is now documented as returning an object containing an array of links, or NULL if there are no switch links.
Calling code may need to be changed; for example, rather than checking if the getLanguageSwitchLinks() return value is FALSE, check if the return value is NULL. Likewise any implementations of LanguageManagerInterface should ensure that the correct object|null type is returned.
