diff --git a/pyproject.toml b/pyproject.toml
index b430d0d..269a045 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "pals_schema"
-version = "0.3.0"
+version = "0.4.0.dev"
 dependencies = [
   "pydantic",
   "pyyaml",