diff --git a/.github/workflows/auto-testing.yml b/.github/workflows/auto-testing.yml
index 3951df9ef..59808e6e0 100644
--- a/.github/workflows/auto-testing.yml
+++ b/.github/workflows/auto-testing.yml
@@ -33,12 +33,6 @@ jobs:
     - name: Ensure generate-code.py doesn't throw any error
       run: |
         python generate-code.py
-    - name: Update version in linebot/__about__.py
-      run: |
-        VERSION="12.3.0"
-        VERSION=${VERSION#v}
-        sed -i "s/__version__ = '__LINE_BOT_SDK_PYTHON_VERSION__'/__version__ = '$VERSION'/g" linebot/__about__.py
-        cat linebot/__about__.py
     - name: Test with pytest
       run: |
         tox
@@ -64,13 +58,6 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
-      - name: Update version in linebot/__about__.py
-        run: |
-          VERSION="12.3.0"
-          VERSION=${VERSION#v}
-          sed -i "s/__version__ = '__LINE_BOT_SDK_PYTHON_VERSION__'/__version__ = '$VERSION'/g" linebot/__about__.py
-          cat linebot/__about__.py
-
       - name: Install dependencies & lib
         run: |
           python -m pip install --upgrade pip
diff --git a/.github/workflows/publish-to-pypi.yml b/.github/workflows/publish-to-pypi.yml
index b29e353f2..8c31725f6 100644
--- a/.github/workflows/publish-to-pypi.yml
+++ b/.github/workflows/publish-to-pypi.yml
@@ -6,6 +6,11 @@ name: Upload Python Package
 on:
   release:
     types: [published]
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'The version to release'
+        required: true
 
 jobs:
   deploy:
@@ -26,10 +31,14 @@ jobs:
         pip install setuptools wheel twine
     - name: Update version in linebot/__about__.py
       run: |
-        VERSION=${{ github.event.release.tag_name }}
+        if [ "${{ github.event_name }}" == "workflow_dispatch" ]; then
+          VERSION=${{ github.event.inputs.version }}
+        else
+          VERSION=${{ github.event.release.tag_name }}
+        fi
+
         VERSION=${VERSION#v}
-        sed -i "s/__version__ = '__LINE_BOT_SDK_PYTHON_VERSION__'/__version__ = '$VERSION'/g" linebot/__about__.py
-        cat linebot/__about__.py
+        python tools/update_version.py $VERSION
     - name: Build and publish
       env:
         TWINE_USERNAME: ${{ secrets.PYPI_API_USER }}
diff --git a/linebot/__about__.py b/linebot/__about__.py
index dbce609c0..b8ea48d3a 100644
--- a/linebot/__about__.py
+++ b/linebot/__about__.py
@@ -15,7 +15,7 @@
 """Meta data of line-bot-sdk."""
 
 
-__version__ = '__LINE_BOT_SDK_PYTHON_VERSION__'
+__version__ = '1.0.0a1'
 __author__ = 'LINE Corporation'
 __copyright__ = 'Copyright 2016, LINE Corporation'
 __license__ = 'Apache 2.0'
diff --git a/tools/update_version.py b/tools/update_version.py
new file mode 100755
index 000000000..ba928ddf7
--- /dev/null
+++ b/tools/update_version.py
@@ -0,0 +1,70 @@
+import sys
+import re
+import subprocess
+
+def update_and_verify_version(new_version):
+    file_path = 'linebot/__about__.py'
+
+    # Update version
+    with open(file_path, 'r') as file:
+        content = file.read()
+
+    new_content = re.sub(
+        r"__version__ = '.*?'",
+        f"__version__ = '{new_version}'",
+        content
+    )
+
+    with open(file_path, 'w') as file:
+        file.write(new_content)
+
+    print(f"Updated version to {new_version} in {file_path}")
+
+    # verify version
+    match = re.search(r"__version__ = '(.*?)'", new_content)
+    if not match:
+        raise ValueError("Version string not found in the file.")
+
+    actual_version = match.group(1)
+    if actual_version != new_version:
+        raise ValueError(f"Version mismatch: expected {new_version}, found {actual_version}")
+
+    print(f"Version verified: {actual_version}")
+
+    # diff check just in case
+    try:
+        result = subprocess.run(['git', 'diff', '--numstat', file_path], capture_output=True, text=True, check=True)
+        changed_lines = result.stdout.strip().split('\n')
+        added_lines = 0
+        deleted_lines = 0
+
+        for line in changed_lines:
+            added, deleted = map(int, line.split('\t')[:2])
+            added_lines += added
+            deleted_lines += deleted
+
+        if added_lines != 1 or deleted_lines != 1:
+            raise ValueError(f"Unexpected number of changed lines: expected 1 added and 1 deleted, found {added_lines} added and {deleted_lines} deleted")
+
+        print('Git diff verification passed: 1 line added and 1 line deleted.')
+
+        # Show diff
+        diff_result = subprocess.run(['git', 'diff', '--color=always', file_path], capture_output=True, text=True, check=True)
+        print('Git diff output:\n', diff_result.stdout)
+
+    except subprocess.CalledProcessError as e:
+        print(f"Error during git diff verification: {e}")
+        sys.exit(1)
+
+if __name__ == "__main__":
+    if len(sys.argv) != 2:
+        print("Usage: python update_version.py <new_version>")
+        sys.exit(1)
+
+    new_version = sys.argv[1]
+
+    try:
+        update_and_verify_version(new_version)
+    except ValueError as e:
+        print(e)
+        sys.exit(1)