diff --git a/src/Symfony/Component/Ldap/Security/LdapUserProvider.php b/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
index 95baed2d65..4e346cceef 100644
--- a/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
+++ b/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
@@ -63,7 +63,7 @@ class LdapUserProvider implements UserProviderInterface
     /**
      * {@inheritdoc}
      */
-    public function loadUserByUsername($username)
+    public function loadUserByUsername(string $username)
     {
         try {
             $this->ldap->bind($this->searchDn, $this->searchPassword);
@@ -112,7 +112,7 @@ class LdapUserProvider implements UserProviderInterface
     /**
      * {@inheritdoc}
      */
-    public function supportsClass($class)
+    public function supportsClass(string $class)
     {
         return LdapUser::class === $class;
     }
diff --git a/src/Symfony/Component/Ldap/composer.json b/src/Symfony/Component/Ldap/composer.json
index ba70fb5bbc..fcdecf712f 100644
--- a/src/Symfony/Component/Ldap/composer.json
+++ b/src/Symfony/Component/Ldap/composer.json
@@ -21,10 +21,11 @@
         "ext-ldap": "*"
     },
     "require-dev": {
-        "symfony/security-core": "^4.4"
+        "symfony/security-core": "^5.0"
     },
     "conflict": {
-        "symfony/options-resolver": "<4.4"
+        "symfony/options-resolver": "<4.4",
+        "symfony/security-core": "<5"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\Ldap\\": "" },