diff --git a/composer.json b/composer.json
index 203080b..c9ff47a 100755
--- a/composer.json
+++ b/composer.json
@@ -29,7 +29,8 @@
 		}
 	],
 	"require": {
-		"php": ">7.2 <8.0"
+		"php": ">7.2 <8.0",
+		"ext-mbstring": "*"
 	},
 	"require-dev": {
 		"monolog/monolog": "^2.8"