diff --git a/builder-web.opam b/builder-web.opam
index fcd61d9..ec2d082 100644
--- a/builder-web.opam
+++ b/builder-web.opam
@@ -37,7 +37,7 @@ depends: [
   "metrics-influx"
   "metrics-rusage"
   "ipaddr"
-  "tyxml" {>= "4.0.0"}
+  "tyxml" {>= "4.3.0"}
   "ptime"
   "duration"
   "mirage-crypto"