diff --git a/composer-require-checker.json b/composer-require-checker.json
index 7dfd157..6d5bb51 100644
--- a/composer-require-checker.json
+++ b/composer-require-checker.json
@@ -1,9 +1,3 @@
 {
-  "scan-files" : ["bin/esb"],
-  "symbol-whitelist": [
-    "null", "true", "false", "static", "self", "parent",
-    "array", "string", "int", "float", "bool", "iterable", "callable", "void", "object", "mixed", "never",
-
-    "mb_convert_encoding"
-  ]
+  "scan-files" : ["bin/esb"]
 }
diff --git a/composer.json b/composer.json
index 473f144..579c430 100644
--- a/composer.json
+++ b/composer.json
@@ -13,6 +13,7 @@
         "php": "~7.4.0|~8.0.0|~8.1.0|~8.2.0|~8.3.0",
         "ext-pcntl": "*",
         "ext-json": "*",
+        "ext-mbstring": "*",
         "symfony/dependency-injection": "^4.3",
         "symfony/config": "^4.3",
         "symfony/yaml": "^4.3",
@@ -38,9 +39,6 @@
         "symfony/deprecation-contracts": "^2.1",
         "amphp/http-server-form-parser": "^1.1"
     },
-    "suggest": {
-        "ext-mbstring": "*"
-    },
     "autoload": {
         "psr-4": {
             "Webgriffe\\Esb\\": ["src/"]