diff --git a/docs/en/source/conf.py b/docs/en/source/conf.py
index 621ac8d..50f7f48 100644
--- a/docs/en/source/conf.py
+++ b/docs/en/source/conf.py
@@ -26,9 +26,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = '1.0'
+version = '1.1-dev'
 # The full version, including alpha/beta/rc tags
-release = '1.0.0'
+release = '1.1-dev'
 
 
 # -- General configuration ---------------------------------------------------
diff --git a/docs/ja/source/conf.py b/docs/ja/source/conf.py
index 22c58d7..9e7e069 100644
--- a/docs/ja/source/conf.py
+++ b/docs/ja/source/conf.py
@@ -26,9 +26,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = '1.0'
+version = '1.1-dev'
 # The full version, including alpha/beta/rc tags
-release = '1.0.0'
+release = '1.1-dev'
 
 
 # -- General configuration ---------------------------------------------------
diff --git a/pyproject.toml b/pyproject.toml
index c3177e3..0d24153 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "HTP-tools-moller"
-version = "1.0"
+version = "1.1-dev"
 description = "High-ThroughtPut calculation tools"
 authors = ["HTP-tools developers <htp-tools-dev@issp.u-tokyo.ac.jp>"]
 license = "GPL-3.0-or-later"
diff --git a/src/moller/__init__.py b/src/moller/__init__.py
index 1f356cc..87d58d5 100644
--- a/src/moller/__init__.py
+++ b/src/moller/__init__.py
@@ -1 +1 @@
-__version__ = '1.0.0'
+__version__ = '1.1-dev'