diff --git a/src/h1_htx.c b/src/h1_htx.c
index 16bc47a..55fc42b 100644
--- a/src/h1_htx.c
+++ b/src/h1_htx.c
@@ -178,7 +178,18 @@
 		h1m->curr_len = h1m->body_len = 0;
 	}
 
+
 	flags = h1m_htx_sl_flags(h1m);
+	if ((flags & (HTX_SL_F_CONN_UPG|HTX_SL_F_BODYLESS)) == HTX_SL_F_CONN_UPG) {
+		int i;
+
+		for (i = 0; hdrs[i].n.len; i++) {
+			if (isteqi(hdrs[i].n, ist("upgrade")))
+				hdrs[i].v = IST_NULL;
+		}
+		h1m->flags &=~ H1_MF_CONN_UPG;
+		flags &= ~HTX_SL_F_CONN_UPG;
+	}
 	sl = htx_add_stline(htx, HTX_BLK_REQ_SL, flags, meth, uri, vsn);
 	if (!sl || !htx_add_all_headers(htx, hdrs))
 		goto error;