diff --git a/opam b/opam
index 2099ce320..7065e6d4f 100644
--- a/opam
+++ b/opam
@@ -20,8 +20,8 @@ build-test: [
 depends: [
   "ocamlbuild" {build}
   "ocamlfind"
-  "camlp5"
-  "ostap"
-  "GT"
-  "re"
+  "camlp5" {= "7.03"}
+  "ostap" {= "0.3"}
+  "GT" {= "0.01"}
+  "re" {= "1.7.1"}
 ]
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