diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
index f3e9f7979..64d70cfea 100644
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -253,7 +253,7 @@ typedef struct {
 
     ngx_str_t                        module;
 
-    NGX_COMPAT_BEGIN(2)
+    NGX_COMPAT_BEGIN(6)
     NGX_COMPAT_END
 } ngx_http_upstream_conf_t;