diff --git a/LICENSE b/LICENSE
index c467ac0..c77c54e 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2017 Tsuyoshi Hombashi
+Copyright (c) 2017-2024 Tsuyoshi Hombashi
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/Makefile b/Makefile
index a8a8ed1..10b0455 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,3 @@
-AUTHOR := thombashi
 PACKAGE := tabledata
 BUILD_WORK_DIR := _work
 DOCS_DIR := docs
@@ -7,12 +6,16 @@ PKG_BUILD_DIR := $(BUILD_WORK_DIR)/$(PACKAGE)
 
 PYTHON := python3
 
+AUTHOR := Tsuyoshi Hombashi
+FIRST_RELEASE_YEAR := 2017
+LAST_UPDATE_YEAR := $(shell git log -1 --format=%cd --date=format:%Y)
+
 
 .PHONY: build-remote
 build-remote: clean
 	@mkdir -p $(BUILD_WORK_DIR)
 	@cd $(BUILD_WORK_DIR) && \
-		git clone https://github.com/$(AUTHOR)/$(PACKAGE).git --depth 1 && \
+		git clone https://github.com/thombashi/$(PACKAGE).git --depth 1 && \
 		cd $(PACKAGE) && \
 		$(PYTHON) -m tox -e build
 	ls -lh $(PKG_BUILD_DIR)/dist/*
@@ -62,3 +65,8 @@ setup-ci:
 setup-dev: setup-ci
 	$(PYTHON) -m pip install -q --disable-pip-version-check --upgrade -e .[test]
 	$(PYTHON) -m pip check
+
+.PHONY: update-copyright
+update-copyright:
+	sed -i "s/f\"Copyright .*/f\"Copyright $(FIRST_RELEASE_YEAR)-$(LAST_UPDATE_YEAR), {__author__}\"/" $(PACKAGE)/__version__.py
+	sed -i "s/^Copyright (c) .* $(AUTHOR)/Copyright (c) $(FIRST_RELEASE_YEAR)-$(LAST_UPDATE_YEAR) $(AUTHOR)/" LICENSE
diff --git a/tabledata/__version__.py b/tabledata/__version__.py
index 64cd01a..a049617 100644
--- a/tabledata/__version__.py
+++ b/tabledata/__version__.py
@@ -2,7 +2,7 @@
 
 
 __author__: Final = "Tsuyoshi Hombashi"
-__copyright__: Final = f"Copyright 2017, {__author__}"
+__copyright__: Final = f"Copyright 2017-2024, {__author__}"
 __license__: Final = "MIT License"
 __version__ = "1.3.3"
 __maintainer__: Final = __author__