Composer 2.3 isn't compatible with wallabag

var/SymfonyRequirements.php

@@ -455,6 +455,12 @@ class SymfonyRequirements extends RequirementCollection
             );
         }
 
+        $this->addRequirement(
+            function_exists('iconv'),
+            'iconv() must be available',
+            'Install and enable the <strong>iconv</strong> extension.'
+        );
+
         $this->addRequirement(
             function_exists('json_encode'),
             'json_encode() must be available',