diff --git a/composer.json b/composer.json
index cd44115..b422830 100644
--- a/composer.json
+++ b/composer.json
@@ -25,8 +25,9 @@
     },
     "require": {
         "php": ">=8.0",
+        "ext-mbstring": "*",
         "brick/math": "^0.9|^0.10|^0.11|^0.12",
-        "ext-mbstring": "*"
+        "symfony/polyfill-mbstring": "^1.28"
     },
     "require-dev": {
         "ext-json": "*",