diff --git a/config/set/php86.php b/config/set/php86.php
index 97225a343b2..e03b104094d 100644
--- a/config/set/php86.php
+++ b/config/set/php86.php
@@ -5,6 +5,8 @@
 use Rector\Config\RectorConfig;
 use Rector\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector;
 use Rector\Php86\Rector\FuncCall\MinMaxToClampRector;
+use Rector\Removing\Rector\FuncCall\RemoveFuncCallArgRector;
+use Rector\Removing\ValueObject\RemoveFuncCallArg;
 use Rector\Renaming\Rector\FuncCall\RenameFunctionRector;
 
 return static function (RectorConfig $rectorConfig): void {
@@ -18,4 +20,7 @@
         'doubleval' => 'floatval',
         '_' => 'gettext',
     ]);
+
+    // https://wiki.php.net/rfc/deprecations_php_8_6#deprecate_define_with_case_insensitive_being_specified
+    $rectorConfig->ruleWithConfiguration(RemoveFuncCallArgRector::class, [new RemoveFuncCallArg('define', 2)]);
 };