diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..3d81993
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,15 @@
+language: c
+env:
+  - OCAML=4.02.3
+  - OCAML=4.03.0
+script:
+  - echo "yes" | sudo add-apt-repository ppa:avsm/ppa
+  - sudo apt-get update -qq
+  - sudo apt-get install -qq opam
+  - export OPAMYES=1
+  - opam init
+  - opam switch $OCAML
+  - eval `opam config env`
+  - opam pin add -n -k path ppx_getenv .
+  - opam install --deps-only -d -t ppx_getenv
+  - opam install -d -t -v ppx_getenv
\ No newline at end of file
diff --git a/_tags b/_tags
index 0bce820..b6a2935 100644
--- a/_tags
+++ b/_tags
@@ -1,4 +1,4 @@
-true: warn(@5@8@10@11@12@14@23@24@26@29@40), bin_annot, safe_string
+true: warn(@5@8@10@11@12@14@23@24@26@29@40), bin_annot, safe_string, cppo_V_OCAML
 
 <src/*.{ml,mli,byte,native}>: package(ppx_tools.metaquot)
 <src_test/*.{ml,byte,native}>: debug, package(oUnit)
diff --git a/myocamlbuild.ml b/myocamlbuild.ml
index 27884a9..b002f23 100644
--- a/myocamlbuild.ml
+++ b/myocamlbuild.ml
@@ -4,8 +4,9 @@ open Ocamlbuild_plugin
 let _ =
   Unix.putenv "PPX_GETENV_CHECK" "42"
 
-let () = dispatch (
-  function
+let () = dispatch (fun phase ->
+  Ocamlbuild_cppo.dispatcher phase;
+  match phase with
   | After_rules ->
     flag ["ocaml"; "compile"; "ppx_byte"] &
       S[A"-ppx"; A"src/ppx_getenv.byte"];
diff --git a/opam b/opam
index f8dd210..ec82b5c 100644
--- a/opam
+++ b/opam
@@ -15,6 +15,7 @@ build-test: [
   "ocamlbuild" "-classic-display" "-use-ocamlfind" "src_test/test_ppx_getenv.byte" "--"
 ]
 depends: [
+  "cppo"         {build}
   "ppx_tools"    {>= "0.99.1"}
   "ounit"        {test}
 ]
diff --git a/pkg/build.ml b/pkg/build.ml
index 6af7d29..ad4dc30 100755
--- a/pkg/build.ml
+++ b/pkg/build.ml
@@ -2,13 +2,16 @@
 #directory "pkg"
 #use "topkg.ml"
 
+let ocamlbuild =
+  "ocamlbuild -use-ocamlfind -classic-display -plugin-tag 'package(cppo_ocamlbuild)'"
+
 let () =
   let oc = open_out "src_test/_tags" in
   output_string oc (if Env.native then "<*.ml>: ppx_native" else "<*.ml>: ppx_byte");
   close_out oc
 
 let () =
-  Pkg.describe "ppx_getenv" ~builder:`OCamlbuild [
+  Pkg.describe "ppx_getenv" ~builder:(`Other (ocamlbuild, "_build")) [
     Pkg.lib "pkg/META";
     Pkg.bin ~auto:true "src/ppx_getenv" ~dst:"../lib/ppx_getenv/ppx_getenv";
     Pkg.doc "README.md";
diff --git a/src/ppx_getenv.ml b/src/ppx_getenv.cppo.ml
similarity index 82%
rename from src/ppx_getenv.ml
rename to src/ppx_getenv.cppo.ml
index 5967179..adccf58 100644
--- a/src/ppx_getenv.ml
+++ b/src/ppx_getenv.cppo.ml
@@ -1,3 +1,7 @@
+#if OCAML_VERSION < (4, 03, 0)
+#define Pconst_string Const_string
+#endif
+
 open Ast_mapper
 open Ast_helper
 open Asttypes
@@ -19,9 +23,9 @@ let getenv_mapper argv =
         | (* Should have a single structure item, which is evaluation of a constant string. *)
           PStr [{ pstr_desc =
                   Pstr_eval ({ pexp_loc  = loc;
-                               pexp_desc = Pexp_constant (Const_string (sym, None))}, _)}] ->
+                               pexp_desc = Pexp_constant (Pconst_string (sym, None))}, _)}] ->
           (* Replace with a constant string with the value from the environment. *)
-          Exp.constant ~loc (Const_string (getenv sym, None))
+          Exp.constant ~loc (Pconst_string (getenv sym, None))
         | _ ->
           raise (Location.Error (
                   Location.error ~loc "[%getenv] accepts a string, e.g. [%getenv \"USER\"]"))