diff --git a/include/types/connection.h b/include/types/connection.h
index bfd6547..0c2d960 100644
--- a/include/types/connection.h
+++ b/include/types/connection.h
@@ -558,6 +558,7 @@
 #define PP2_TYPE_AUTHORITY      0x02
 #define PP2_TYPE_CRC32C         0x03
 #define PP2_TYPE_NOOP           0x04
+#define PP2_TYPE_UNIQUE_ID      0x05
 #define PP2_TYPE_SSL            0x20
 #define PP2_SUBTYPE_SSL_VERSION 0x21
 #define PP2_SUBTYPE_SSL_CN      0x22