Update composer and version

composer.json

@@ -1,7 +1,7 @@
 {
   "name": "getkirby/cms",
   "description": "The Kirby 3 core",
-  "version": "3.3.1",
+  "version": "3.3.2-rc.1",
   "license": "proprietary",
   "keywords": ["kirby", "cms", "core"],
   "homepage": "https://getkirby.com",

vendor/symfony/polyfill-mbstring/Mbstring.php

@@ -512,7 +512,9 @@ public static function mb_strrpos($haystack, $needle, $offset = 0, $encoding = n
             $offset = 0;
         } elseif ($offset = (int) $offset) {
             if ($offset < 0) {
-                $haystack = self::mb_substr($haystack, 0, $offset, $encoding);
+                if (0 > $offset += self::mb_strlen($needle)) {
+                    $haystack = self::mb_substr($haystack, 0, $offset, $encoding);
+                }
                 $offset = 0;
             } else {
                 $haystack = self::mb_substr($haystack, $offset, 2147483647, $encoding);
@@ -532,7 +534,7 @@ public static function mb_str_split($string, $split_length = 1, $encoding = null
             return null;
         }
 
-        if ($split_length < 1) {
+        if (1 > $split_length = (int) $split_length) {
             trigger_error('The length of each segment must be greater than zero', E_USER_WARNING);
 
             return false;
@@ -542,6 +544,10 @@ public static function mb_str_split($string, $split_length = 1, $encoding = null
             $encoding = mb_internal_encoding();
         }
 
+        if ('UTF-8' === $encoding = self::getEncoding($encoding)) {
+            return preg_split("/(.{{$split_length}})/u", $string, null, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
+        }
+
         $result = array();
         $length = mb_strlen($string, $encoding);
 
@@ -815,11 +821,16 @@ private static function getEncoding($encoding)
             return self::$internalEncoding;
         }
 
+        if ('UTF-8' === $encoding) {
+            return 'UTF-8';
+        }
+
         $encoding = strtoupper($encoding);
 
         if ('8BIT' === $encoding || 'BINARY' === $encoding) {
             return 'CP850';
         }
+
         if ('UTF8' === $encoding) {
             return 'UTF-8';
         }