diff --git a/openflow_input/standard-1.2 b/openflow_input/standard-1.2
index e4c8ec2..bfa9a64 100644
--- a/openflow_input/standard-1.2
+++ b/openflow_input/standard-1.2
@@ -483,7 +483,7 @@
     uint8_t type == 4;
     uint16_t length;
     uint32_t xid;
-    uint32_t experimenter;
+    uint32_t experimenter == ?;
     uint32_t subtype;
     of_octets_t data;
 };
@@ -699,7 +699,7 @@
 struct of_action_experimenter : of_action {
     uint16_t type == 65535;
     uint16_t len;
-    uint32_t experimenter;
+    uint32_t experimenter == ?;
     of_octets_t data;
 };
 
@@ -753,7 +753,7 @@
 struct of_instruction_experimenter : of_instruction {
     uint16_t type == 65535;
     uint16_t len;
-    uint32_t experimenter;
+    uint32_t experimenter == ?;
     of_octets_t data;
 };
 
@@ -1317,7 +1317,7 @@
     uint16_t stats_type == 0xffff;
     uint16_t flags;
     pad(4);
-    uint32_t experimenter;
+    uint32_t experimenter == ?;
     uint32_t subtype;
     of_octets_t data;
 };
@@ -1330,7 +1330,7 @@
     uint16_t stats_type == 0xffff;
     uint16_t flags;
     pad(4);
-    uint32_t experimenter;
+    uint32_t experimenter == ?;
     uint32_t subtype;
     of_octets_t data;
 };
@@ -1363,7 +1363,7 @@
     uint16_t type == 65535;
     uint16_t len;
     pad(4);
-    uint32_t experimenter;
+    uint32_t experimenter == ?;
     pad(4);
     of_octets_t data;
 };