diff --git a/opam b/opam
index 51a80a86..d633f9ff 100644
--- a/opam
+++ b/opam
@@ -33,6 +33,9 @@ depends: [
     "ocamlbuild" {build}
 ]
 depopts: [ "sequence" "base-bigarray" "base-unix" "base-threads" ]
+conflicts: [
+  "sequence" { < "0.5" }
+]
 tags: [ "stdlib" "containers" "iterators" "list" "heap" "queue" ]
 homepage: "https://github.com/c-cube/ocaml-containers/"
 doc: "http://cedeela.fr/~simon/software/containers/"