diff --git a/src/version.cpp b/src/version.cpp
index 9e09fdd..60e52e4 100644
--- a/src/version.cpp
+++ b/src/version.cpp
@@ -8,7 +8,7 @@
 namespace shiguredo::mp4 {
 
 std::string get_version_string() {
-  return "2022.1.0";
+  return "2023.1.1";
 }
 
 }  // namespace shiguredo::mp4
diff --git a/test/version.cpp b/test/version.cpp
index 70d3f0b..c6e2fab 100644
--- a/test/version.cpp
+++ b/test/version.cpp
@@ -7,7 +7,7 @@
 BOOST_AUTO_TEST_SUITE(version)
 
 BOOST_AUTO_TEST_CASE(version_string) {
-  BOOST_REQUIRE_EQUAL("2022.1.0", shiguredo::mp4::get_version_string());
+  BOOST_REQUIRE_EQUAL("2023.1.1", shiguredo::mp4::get_version_string());
 }
 
 BOOST_AUTO_TEST_SUITE_END()