diff --git a/pyproject.toml b/pyproject.toml
index 0fe374d..5828267 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ requires = ["flit_core >=3.8.0,<4"]
 
 [project]
 name = "rougail.output_formatter"
-version = "0.1.0a27"
+version = "1.0.0rc0"
 authors = [{name = "Emmanuel Garette", email = "gnunux@gnunux.info"}]
 readme = "README.md"
 description = "Rougail output formatter"
diff --git a/src/rougail/output_formatter/__version__.py b/src/rougail/output_formatter/__version__.py
index bc9d386..bcf7f89 100644
--- a/src/rougail/output_formatter/__version__.py
+++ b/src/rougail/output_formatter/__version__.py
@@ -1 +1 @@
-__version__ = "0.1.0a27"
+__version__ = "1.0.0rc0"