diff --git a/ocaml-integers.spec b/ocaml-integers.spec
index a77d646..832ed24 100644
--- a/ocaml-integers.spec
+++ b/ocaml-integers.spec
@@ -1,34 +1,37 @@
 Name:          ocaml-integers
-Version:       0.2.2
-Release:       2mamba
+Version:       0.4.0
+Release:       1mamba
 Summary:       Various signed and unsigned integer types for OCaml
 Group:         System/Libraries/OCaml
 Vendor:        openmamba
 Distribution:  openmamba
 Packager:      Silvan Calarco <silvan.calarco@mambasoft.it>
 URL:           https://github.com/ocamllabs/ocaml-integers
-## GITSOURCE https://github.com/ocamllabs/ocaml-integers.git 0.3.0
-Source:        https://github.com/ocamllabs/ocaml-integers.git/v%{version}/ocaml-integers-%{version}.tar.bz2
+Source:        https://github.com/ocamllabs/ocaml-integers.git/%{version}/ocaml-integers-%{version}.tar.bz2
 License:       MIT
 ## AUTOBUILDREQ-BEGIN
 BuildRequires: glibc-devel
+BuildRequires: ldconfig
+BuildRequires: ocaml-runtime
 ## AUTOBUILDREQ-END
 BuildRequires: dune
-BuildRequires: ocaml >= 4.09.0-4mamba
-BuildRequires: ocaml-findlib-devel >= 1.8.1-3mamba
-BuildRequires: ocamlbuild >= 0.14.0-3mamba
+BuildRequires: ocaml >= 4.11.1
+BuildRequires: ocaml-findlib-devel >= 1.8.1-4mamba
+BuildRequires: ocamlbuild >= 0.14.0-4mamba
 BuildRequires: opam
-BuildRequires: ocaml-topkg
+BuildRequires: ocaml-topkg >= 1.0.3
 BuildRoot:     %{_tmppath}/%{name}-%{version}-root
 
 %description
 The ocaml-integers library provides a number of 8-, 16-, 32- and 64-bit signed and unsigned integer types, together with aliases such as `long` and `size_t` whose sizes depend on the host platform.
 
+%debug_package
+
 %prep
 %setup -q
 
 %build
-%make
+dune build --profile release
 
 %install
 [ "%{buildroot}" != / ] && rm -rf "%{buildroot}"
@@ -36,8 +39,9 @@ opam-installer \
     --prefix=%{buildroot}%{_prefix} \
     --libdir=%{buildroot}$(ocamlc -where) \
     --docdir=%{buildroot}%{_docdir} \
-    --stubsdir=%{buildroot}$(ocamlc -where)/stublibs
-
+    --stubsdir=%{buildroot}$(ocamlc -where)/stublibs \
+	./_build/default/integers.install		 
+		 
 %clean
 [ "%{buildroot}" != / ] && rm -rf "%{buildroot}"
 
@@ -45,12 +49,15 @@ opam-installer \
 %defattr(-,root,root)
 %dir %{_libdir}/ocaml/integers
 %{_libdir}/ocaml/integers/*
-%{_libdir}/ocaml/stublibs/dllintegers.so
+%{_libdir}/ocaml/stublibs/dllintegers_stubs.so
 %dir %{_datadir}/doc/integers
 %{_datadir}/doc/integers/*
 %doc LICENSE.md
 
 %changelog
+* Thu Jan 21 2021 Silvan Calarco <silvan.calarco@mambasoft.it> 0.4.0-1mamba
+- update to 0.4.0
+
 * Mon Dec 30 2019 Silvan Calarco <silvan.calarco@mambasoft.it> 0.2.2-2mamba
 - rebuilt with ocaml 4.09.0-4mamba