diff --git a/src/support/bags/firehub.RequestHeaders.php b/src/support/bags/firehub.RequestHeaders.php
index e090850c6..1d166ee95 100644
--- a/src/support/bags/firehub.RequestHeaders.php
+++ b/src/support/bags/firehub.RequestHeaders.php
@@ -371,9 +371,9 @@ protected function adapt ():array {
             'expect' => 'HTTP_EXCEPT',
             'forwarded' => 'HTTP_FORWARDED',
             'from' => 'HTTP_FROM',
-            'if_modified_since' => 'HTTP_IF-MODIFIED-SINCE',
-            'if_unmodified_since' => 'HTTP_IF-UNMODIFIED-SINCE',
-            'if_none_match' => 'HTTP_IF-NONE-MATCH',
+            'if_modified_since' => 'HTTP_IF_MODIFIED_SINCE',
+            'if_unmodified_since' => 'HTTP_IF_UNMODIFIED_SINCE',
+            'if_none_match' => 'HTTP_IF_NONE_MATCH',
             'permissions_policy' => 'HTTP_PERMISSIONS-POLICY',
             'remote_address' => 'REMOTE_ADDR',
             'remote_address_forwarded' => 'HTTP_X_FORWARDED_FOR',