diff --git a/include/haproxy/http_ana-t.h b/include/haproxy/http_ana-t.h
index 50fbd3de8..89d41dd7b 100644
--- a/include/haproxy/http_ana-t.h
+++ b/include/haproxy/http_ana-t.h
@@ -89,6 +89,7 @@
 #define HTTP_MSGF_COMPRESSING 0x00000020  /* data compression is in progress */
 
 #define HTTP_MSGF_BODYLESS    0x00000040  /* The message has no body (content-length = 0) */
+#define HTTP_MSGF_CONN_UPG    0x00000080  /* The message contains "Connection: Upgrade" header */
 
 /* Maximum length of the cache secondary key (sum of all the possible parts of
  * the secondary key). The actual keys might be smaller for some
diff --git a/include/haproxy/htx-t.h b/include/haproxy/htx-t.h
index fb015752f..f14bb25e5 100644
--- a/include/haproxy/htx-t.h
+++ b/include/haproxy/htx-t.h
@@ -137,7 +137,7 @@
 #define HTX_SL_F_SCHM_HTTPS     0x00000200 /* The scheme HTTPS should be used */
 #define HTX_SL_F_HAS_AUTHORITY  0x00000400 /* The request authority is explicitly specified */
 #define HTX_SL_F_NORMALIZED_URI 0x00000800 /* The received URI is normalized (an implicit absolute-uri form) */
-
+#define HTX_SL_F_CONN_UPG       0x00001000 /* The message contains "connection: upgrade" header */
 
 /* HTX flags */
 #define HTX_FL_NONE              0x00000000
diff --git a/src/h1_htx.c b/src/h1_htx.c
index 30e2b229e..dc6accabb 100644
--- a/src/h1_htx.c
+++ b/src/h1_htx.c
@@ -148,6 +148,8 @@ static unsigned int h1m_htx_sl_flags(struct h1m *h1m)
 	}
 	if (h1m->state == H1_MSG_TUNNEL)
 		flags |= HTX_SL_F_BODYLESS;
+	if (h1m->flags & H1_MF_CONN_UPG)
+		flags |= HTX_SL_F_CONN_UPG;
 	return flags;
 }
 
diff --git a/src/http_ana.c b/src/http_ana.c
index 7816ad563..96753c0ef 100644
--- a/src/http_ana.c
+++ b/src/http_ana.c
@@ -166,6 +166,8 @@ int http_wait_for_request(struct stream *s, struct channel *req, int an_bit)
 		msg->flags |= HTTP_MSGF_TE_CHNK;
 	if (sl->flags & HTX_SL_F_BODYLESS)
 		msg->flags |= HTTP_MSGF_BODYLESS;
+	if (sl->flags & HTX_SL_F_CONN_UPG)
+		msg->flags |= HTTP_MSGF_CONN_UPG;
 
 	/* we can make use of server redirect on GET and HEAD */
 	if (txn->meth == HTTP_METH_GET || txn->meth == HTTP_METH_HEAD)
@@ -1558,6 +1560,8 @@ int http_wait_for_response(struct stream *s, struct channel *rep, int an_bit)
 	}
 	if (sl->flags & HTX_SL_F_BODYLESS)
 		msg->flags |= HTTP_MSGF_BODYLESS;
+	if (sl->flags & HTX_SL_F_CONN_UPG)
+		msg->flags |= HTTP_MSGF_CONN_UPG;
 
 	n = txn->status / 100;
 	if (n < 1 || n > 5)