git subrepo commit mailcow/src/mailcow-dockerized

subrepo: subdir:   "mailcow/src/mailcow-dockerized"
  merged:   "308860af"
upstream: origin:   "https://github.com/mailcow/mailcow-dockerized.git"
  branch:   "master"
  commit:   "3f1a5af8"
git-subrepo: version:  "0.4.5"
  origin:   "???"
  commit:   "???"
Change-Id: I5d51c14b45db54fe706be40a591ddbfcea50d4b0
diff --git a/mailcow/src/mailcow-dockerized/data/web/inc/lib/vendor/symfony/polyfill-mbstring/Mbstring.php b/mailcow/src/mailcow-dockerized/data/web/inc/lib/vendor/symfony/polyfill-mbstring/Mbstring.php
index b599095..b65c54a 100644
--- a/mailcow/src/mailcow-dockerized/data/web/inc/lib/vendor/symfony/polyfill-mbstring/Mbstring.php
+++ b/mailcow/src/mailcow-dockerized/data/web/inc/lib/vendor/symfony/polyfill-mbstring/Mbstring.php
@@ -80,7 +80,7 @@
 
     public static function mb_convert_encoding($s, $toEncoding, $fromEncoding = null)
     {
-        if (\is_array($fromEncoding) || false !== strpos($fromEncoding, ',')) {
+        if (\is_array($fromEncoding) || ($fromEncoding !== null && false !== strpos($fromEncoding, ','))) {
             $fromEncoding = self::mb_detect_encoding($s, $fromEncoding);
         } else {
             $fromEncoding = self::getEncoding($fromEncoding);
@@ -602,6 +602,9 @@
         if (80000 > \PHP_VERSION_ID) {
             return false;
         }
+        if (\is_int($c) || 'long' === $c || 'entity' === $c) {
+            return false;
+        }
 
         throw new \ValueError('Argument #1 ($substitute_character) must be "none", "long", "entity" or a valid codepoint');
     }