diff --git a/composer.json b/composer.json
index a6d3b2d6..40b564f2 100644
--- a/composer.json
+++ b/composer.json
@@ -12,7 +12,8 @@
         "symfony/intl": "^4.4|^5.0|^6.0|^7.0",
         "kmukku/php-iso11649": "^1.5",
         "endroid/qr-code": "^4.4.4|^5.0",
-        "symfony/polyfill-intl-icu": "^1.23"
+        "symfony/polyfill-intl-icu": "^1.23",
+        "symfony/polyfill-mbstring": "^1.30"
     },
     "require-dev": {
         "phpunit/phpunit": "^9.0",