diff --git a/pyproject.toml b/pyproject.toml
index 3399210..e3537bc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,7 +1,7 @@
 [project]
 name = "takopi"
 authors = [{name = "banteg"}]
-version = "0.3.0"
+version = "0.4.0.dev0"
 description = "Run OpenAI Codex CLI with Telegram as the human-in-the-loop interface."
 readme = "readme.md"
 license = { file = "LICENSE" }
diff --git a/src/takopi/__init__.py b/src/takopi/__init__.py
index 493f741..52c6947 100644
--- a/src/takopi/__init__.py
+++ b/src/takopi/__init__.py
@@ -1 +1 @@
-__version__ = "0.3.0"
+__version__ = "0.4.0.dev0"
diff --git a/uv.lock b/uv.lock
index 11261d1..89ed3d5 100644
--- a/uv.lock
+++ b/uv.lock
@@ -354,7 +354,7 @@ wheels = [
 
 [[package]]
 name = "takopi"
-version = "0.3.0"
+version = "0.4.0.dev0"
 source = { editable = "." }
 dependencies = [
     { name = "anyio" },