diff --git a/Mbstring.php b/Mbstring.php
index <HASH>..<HASH> 100644
--- a/Mbstring.php
+++ b/Mbstring.php
@@ -568,7 +568,7 @@ final class Mbstring
             }
             $rx .= '.{'.$split_length.'})/us';
 
-            return preg_split($rx, $string, null, \PREG_SPLIT_DELIM_CAPTURE | \PREG_SPLIT_NO_EMPTY);
+            return preg_split($rx, $string, -1, \PREG_SPLIT_DELIM_CAPTURE | \PREG_SPLIT_NO_EMPTY);
         }
 
         $result = [];
Passing null to preg_split() throws deprecation on PHP <I>

> preg_split(): Passing null to parameter #3 ($limit) of type int is deprecated