diff --git a/ppx_deriving_cmdliner.opam b/ppx_deriving_cmdliner.opam
index a24d610..3254038 100644
--- a/ppx_deriving_cmdliner.opam
+++ b/ppx_deriving_cmdliner.opam
@@ -12,7 +12,7 @@ bug-reports: "https://github.com/hammerlab/ppx_deriving_cmdliner/issues"
 dev-repo: "git+https://github.com/hammerlab/ppx_deriving_cmdliner.git"
 doc: "http://hammerlab.github.io/ppx_deriving_cmdliner"
 license: "MIT"
-version: "0.4.2-dev"
+version: "0.5.1-dev"
 tags: ["syntax" "cli"]
 build: [
   ["dune" "subst"] {pinned}