diff --git a/packages/erm_xmpp.0.4~dev/opam b/packages/erm_xmpp.0.4~dev/opam
index c3ee2d5..fb40a8b 100644
--- a/packages/erm_xmpp.0.4~dev/opam
+++ b/packages/erm_xmpp.0.4~dev/opam
@@ -11,6 +11,7 @@ depends: [
   "mirage-crypto"
   "mirage-crypto-rng"
   "base64" {>= "3.0.0"}
+  "cstruct" {>= "6.0.0"}
 ]
 flags: light-uninstall
 build: [