diff --git a/composer.json b/composer.json
index 3ec28e0..69c5015 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,7 @@
         "php": ">=7.2",
         "doctrine/lexer": "^1.2",
         "doctrine/collections": "^1.6",
-        "patchwork/utf8": ">=1.3"
+        "symfony/polyfill-mbstring": "^1.23"
     },
     "require-dev": {
         "phpunit/phpunit": "^9.5"
diff --git a/src/ReverseRegex/Parser/CharacterClass.php b/src/ReverseRegex/Parser/CharacterClass.php
index 57f3dc0..5618ffa 100644
--- a/src/ReverseRegex/Parser/CharacterClass.php
+++ b/src/ReverseRegex/Parser/CharacterClass.php
@@ -5,7 +5,6 @@
 use ReverseRegex\Generator\LiteralScope;
 use ReverseRegex\Lexer;
 use ReverseRegex\Exception as ParserException;
-use Patchwork\Utf8;
 
 /**
   *  Parse a character class [0-9][a-z]
@@ -108,7 +107,7 @@ public function parse(Scope $head, Scope $set, Lexer $lexer)
                     
                 break;    
                 case($normal_lexer->isNextToken(Lexer::T_LITERAL_NUMERIC) || $normal_lexer->isNextToken(Lexer::T_LITERAL_CHAR)) :
-                    $index = (integer)Utf8::ord($normal_lexer->lookahead['value']);
+                    $index = (integer)mb_ord($normal_lexer->lookahead['value']);
                     $head->setLiteral($index,$normal_lexer->lookahead['value']);
                 break;
                 default:
@@ -131,15 +130,15 @@ public function parse(Scope $head, Scope $set, Lexer $lexer)
     public function fillRange(Scope $head,$start,$end)
     {
         
-        $start_index  = Utf8::ord($start);
-        $ending_index = Utf8::ord($end);
+        $start_index  = mb_ord($start);
+        $ending_index = mb_ord($end);
         
         if($ending_index < $start_index ) {
             throw new ParserException(sprintf('Character class range %s - %s is out of order',$start,$end));
         }
         
         for($i = $start_index; $i <= $ending_index; $i++) {
-            $head->setLiteral($i,Utf8::chr($i));
+            $head->setLiteral($i,mb_chr($i));
         }    
     }
   
diff --git a/src/ReverseRegex/Parser/Unicode.php b/src/ReverseRegex/Parser/Unicode.php
index 84445e4..64bfd89 100644
--- a/src/ReverseRegex/Parser/Unicode.php
+++ b/src/ReverseRegex/Parser/Unicode.php
@@ -4,7 +4,6 @@
 use ReverseRegex\Generator\Scope;
 use ReverseRegex\Lexer;
 use ReverseRegex\Exception as ParserException;
-use Patchwork\Utf8;
 
 /**
   *  Parse a unicode sequence e.g  \x54 \X{4444}
@@ -74,7 +73,7 @@ public function evaluate(Lexer $lexer)
                 
                 $number    = trim(implode('',$tokens));
                 
-                return Utf8::chr(hexdec($number));
+                return mb_chr(hexdec($number));
                 
             break;
             case ($lexer->isNextToken(Lexer::T_SHORT_X)) :
@@ -92,7 +91,7 @@ public function evaluate(Lexer $lexer)
                 }
                 
                 $value     = trim(implode('',$tokens));
-                return Utf8::chr(hexdec($value));
+                return mb_chr(hexdec($value));
             break;
             default :
                 throw new ParserException('No Unicode expression to evaluate');