diff --git a/pyproject.toml b/pyproject.toml
index d785e4e..b1731a8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -5,7 +5,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "fiduswriter-languagetool"
 description = "A Fidus Writer plugin to connect to Languagetool."
-version = "3.12.0-dev"
+version = "4.0.0rc1"
 readme = "README.md"
 license = {text = "AGPL-3.0-or-later"}
 authors = [