+ /**
+ * Mapping of deprecated language codes that were used in previous
+ * versions of MediaWiki to up-to-date, current language codes.
+ *
+ * @var array Mapping from language code to language code
+ *
+ * @since 1.30
+ */
+ private static $deprecatedLanguageCodeMapping = [
+ // Note that als is actually a valid ISO 639 code (Tosk Albanian), but it
+ // was previously used in MediaWiki for Alsatian, which comes under gsw
+ 'als' => 'gsw',
+ 'bat-smg' => 'sgs',
+ 'be-x-old' => 'be-tarask',
+ 'fiu-vro' => 'vro',
+ 'roa-rup' => 'rup',
+ 'zh-classical' => 'lzh',
+ 'zh-min-nan' => 'nan',
+ 'zh-yue' => 'yue',
+ ];
+