diff --git a/ocaml-lilv.spec b/ocaml-lilv.spec
index 39d69ac..d3c0bf7 100644
--- a/ocaml-lilv.spec
+++ b/ocaml-lilv.spec
@@ -2,7 +2,7 @@
 
 Name:          ocaml-lilv
 Version:       0.1.0
-Release:       1mamba
+Release:       2mamba
 Summary:       OCaml bindings to the lilv library for using LV2 plugins
 Group:         System/Libraries/OCaml
 Vendor:        openmamba
@@ -25,6 +25,7 @@ BuildRequires: ocaml-integers
 BuildRequires: dune
 BuildRequires: ocaml
 BuildRequires: ocaml-findlib
+BuildRequires: ocaml-ctypes-devel >= 0.20.1
 
 %description
 %{summary}.
@@ -72,5 +73,8 @@ rm -rf %{buildroot}/usr/doc
 %doc CHANGES* README.md
 
 %changelog
+* Thu May 19 2022 Silvan Calarco <silvan.calarco@mambasoft.it> 0.1.0-2mamba
+- rebuilt with ocaml-ctypes 0.20.1
+
 * Fri Feb 11 2022 Silvan Calarco <silvan.calarco@mambasoft.it> 0.1.0-1mamba
 - package created using the webbuild interface