diff --git a/pyproject.toml b/pyproject.toml
index c671a8e1..9883413b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = 'setuptools.build_meta'
 
 [project]
 name = 'stimuli'
-version = '0.4.0.dev'
+version = '0.4.0'
 description = 'Simple auditory and visual stimuli avoiding PsychoPy.'
 readme = 'README.md'
 license = {file = 'LICENSE'}