$cache = ObjectCache::getLocalServerInstance( CACHE_ANYTHING );
$cacheKey = $cache->makeKey(
'first-letters',
+ static::class,
$this->locale,
$this->digitTransformLanguage->getCode(),
self::getICUVersion(),
* can't be determined.
*
* The constant INTL_ICU_VERSION this function refers to isn't really
- * documented. It is available since PHP 5.3.7 (see PHP bug 54561).
- * This function will return false on older PHPs.
+ * documented. It is available since PHP 5.3.7 (see PHP 54561
+ * https://bugs.php.net/bug.php?id=54561). This function will return
+ * false on older PHPs.
+ *
+ * TODO: Remove the backwards-compatibility as MediaWiki now requires
+ * higher levels of PHP.
*
* @since 1.21
* @return string|bool