diff --git a/dune-project b/dune-project
index a3e9e081da..0344c66c20 100644
--- a/dune-project
+++ b/dune-project
@@ -34,6 +34,7 @@
  (conflicts
   (ocamlfind (< 1.5.1))
   (js_of_ocaml (< 3.0))
+  (base (= v0.16.0))
 ))
 
 (package
diff --git a/js_of_ocaml-compiler.opam b/js_of_ocaml-compiler.opam
index 0630d7b7c1..880dbbc485 100644
--- a/js_of_ocaml-compiler.opam
+++ b/js_of_ocaml-compiler.opam
@@ -30,6 +30,7 @@ depopts: ["ocamlfind"]
 conflicts: [
   "ocamlfind" {< "1.5.1"}
   "js_of_ocaml" {< "3.0"}
+  "base" {= "v0.16.0"}
 ]
 dev-repo: "git+https://github.com/ocsigen/js_of_ocaml.git"
 build: [