diff --git a/.github/workflows/android.yaml b/.github/workflows/android.yaml
index e851407fd..eec7010f5 100644
--- a/.github/workflows/android.yaml
+++ b/.github/workflows/android.yaml
@@ -13,8 +13,8 @@ concurrency:
 
 jobs:
   build:
-    # https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2204-Readme.md
-    runs-on: ubuntu-22.04
+    # https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2404-Readme.md
+    runs-on: ubuntu-24.04
     timeout-minutes: 60
 
     steps:
diff --git a/.github/workflows/linux.yaml b/.github/workflows/linux.yaml
index 7029da5ca..13d001b4d 100644
--- a/.github/workflows/linux.yaml
+++ b/.github/workflows/linux.yaml
@@ -13,8 +13,8 @@ concurrency:
 
 jobs:
   build:
-    # https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2204-Readme.md
-    runs-on: ubuntu-22.04
+    # https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2404-Readme.md
+    runs-on: ubuntu-24.04
     timeout-minutes: 60
 
     steps:
@@ -30,9 +30,6 @@ jobs:
           #
           # Unset the Android NDK setting to skip the unnecessary configuration.
           echo "ANDROID_NDK_HOME=" >> $GITHUB_ENV
-          #
-          # Work around https://bugreports.qt.io/browse/QTBUG-86080 for Ubuntu 22.04
-          echo "PKG_CONFIG_PATH=${PWD}/docker/ubuntu22.04/qt6-core-pkgconfig:${PKG_CONFIG_PATH}" >> $GITHUB_ENV
 
       - name: bazel build
         working-directory: ./src
@@ -47,8 +44,8 @@ jobs:
           if-no-files-found: warn
 
   test:
-    # https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2204-Readme.md
-    runs-on: ubuntu-22.04
+    # https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2404-Readme.md
+    runs-on: ubuntu-24.04
     timeout-minutes: 60
 
     steps:
@@ -64,9 +61,6 @@ jobs:
           #
           # Unset the Android NDK setting to skip the unnecessary configuration.
           echo "ANDROID_NDK_HOME=" >> $GITHUB_ENV
-          #
-          # Work around https://bugreports.qt.io/browse/QTBUG-86080 for Ubuntu 22.04
-          echo "PKG_CONFIG_PATH=${PWD}/docker/ubuntu22.04/qt6-core-pkgconfig:${PKG_CONFIG_PATH}" >> $GITHUB_ENV
 
       - name: bazel test
         working-directory: ./src
diff --git a/docs/build_mozc_in_docker.md b/docs/build_mozc_in_docker.md
index a4106d1ef..c82af6f8c 100644
--- a/docs/build_mozc_in_docker.md
+++ b/docs/build_mozc_in_docker.md
@@ -9,9 +9,9 @@ If you are not sure what the following commands do, please check the description
 and make sure the operations before running them.
 
 ```
-curl -O https://raw.githubusercontent.com/google/mozc/master/docker/ubuntu22.04/Dockerfile
-docker build --rm --tag mozc_ubuntu22.04 .
-docker create --interactive --tty --name mozc_build mozc_ubuntu22.04
+curl -O https://raw.githubusercontent.com/google/mozc/master/docker/ubuntu24.04/Dockerfile
+docker build --rm --tag mozc_ubuntu24.04 .
+docker create --interactive --tty --name mozc_build mozc_ubuntu24.04
 
 docker start mozc_build
 docker exec mozc_build bazel build package --config oss_linux --config release_build
@@ -22,24 +22,24 @@ docker cp mozc_build:/home/mozc_builder/work/mozc/src/bazel-bin/unix/mozc.zip .
 Docker containers are available to build Mozc binaries for Android JNI library and Linux desktop.
 
 ## System Requirements
-Currently, only Ubuntu 22.04 is tested to host the Docker container to build Mozc.
+Currently, only Ubuntu 24.04 is tested to host the Docker container to build Mozc.
 
-* [Dockerfile](https://github.com/google/mozc/blob/master/docker/ubuntu22.04/Dockerfile) for Ubuntu 22.04
+* [Dockerfile](https://github.com/google/mozc/blob/master/docker/ubuntu24.04/Dockerfile) for Ubuntu 24.04
 
 ## Build in Docker
 
-### Set up Ubuntu 22.04 Docker container
+### Set up Ubuntu 24.04 Docker container
 
 ```
-curl -O https://raw.githubusercontent.com/google/mozc/master/docker/ubuntu22.04/Dockerfile
-docker build --rm --tag mozc_ubuntu22.04 .
-docker create --interactive --tty --name mozc_build mozc_ubuntu22.04
+curl -O https://raw.githubusercontent.com/google/mozc/master/docker/ubuntu24.04/Dockerfile
+docker build --rm --tag mozc_ubuntu24.04 .
+docker create --interactive --tty --name mozc_build mozc_ubuntu24.04
 ```
 
 You may need to execute `docker` with `sudo` (e.g. `sudo docker build ...`).
 
 Notes
-* `mozc_ubuntu22.04` is a Docker image name (customizable).
+* `mozc_ubuntu24.04` is a Docker image name (customizable).
 * `mozc_build` is a Docker container name (customizable).
 * Don't forget to rebuild Docker container when Dockerfile is updated.
 
@@ -148,7 +148,7 @@ Note: This section is not about our officially supported build process.
 
 You may also need other libraries.
 See the configurations of
-[Dockerfile](https://github.com/google/mozc/blob/master/docker/ubuntu22.04/Dockerfile)
+[Dockerfile](https://github.com/google/mozc/blob/master/docker/ubuntu24.04/Dockerfile)
 and
 [GitHub Actions](https://github.com/google/mozc/blob/master/.github/workflows/linux.yaml).
 
diff --git a/docs/build_mozc_in_osx.md b/docs/build_mozc_in_osx.md
index ffaf04c4d..524c869f3 100644
--- a/docs/build_mozc_in_osx.md
+++ b/docs/build_mozc_in_osx.md
@@ -87,7 +87,7 @@ python build_tools/update_deps.py
 In this step, additional build dependencies will be downloaded.
 
   * [Ninja 1.11.0](https://github.com/ninja-build/ninja/releases/download/v1.11.0/ninja-mac.zip)
-  * [Qt 6.7.2](https://download.qt.io/archive/qt/6.7/6.7.2/submodules/qtbase-everywhere-src-6.7.2.tar.xz)
+  * [Qt 6.7.3](https://download.qt.io/archive/qt/6.7/6.7.3/submodules/qtbase-everywhere-src-6.7.3.tar.xz)
   * [git submodules](../.gitmodules)
 
 You can specify `--noqt` option if you would like to use your own Qt binaries.
diff --git a/docs/build_mozc_in_windows.md b/docs/build_mozc_in_windows.md
index 8d683c6f9..463b2bc36 100644
--- a/docs/build_mozc_in_windows.md
+++ b/docs/build_mozc_in_windows.md
@@ -65,7 +65,7 @@ python build_tools/update_deps.py
 In this step, additional build dependencies will be downloaded.
 
   * [Ninja 1.11.0](https://github.com/ninja-build/ninja/releases/download/v1.11.0/ninja-win.zip)
-  * [Qt 6.7.2](https://download.qt.io/archive/qt/6.7/6.7.2/submodules/qtbase-everywhere-src-6.7.2.tar.xz)
+  * [Qt 6.7.3](https://download.qt.io/archive/qt/6.7/6.7.3/submodules/qtbase-everywhere-src-6.7.3.tar.xz)
   * [.NET tools](../dotnet-tools.json)
   * [git submodules](../.gitmodules)
 
diff --git a/src/base/util.cc b/src/base/util.cc
index b03c32690..55daee5be 100644
--- a/src/base/util.cc
+++ b/src/base/util.cc
@@ -329,6 +329,23 @@ size_t Util::CharsLen(absl::string_view str) {
   return length;
 }
 
+std::u32string Util::Utf8ToUtf32(absl::string_view str) {
+  std::u32string codepoints;
+  char32_t codepoint;
+  while (Util::SplitFirstChar32(str, &codepoint, &str)) {
+    codepoints.push_back(codepoint);
+  }
+  return codepoints;
+}
+
+std::string Util::Utf32ToUtf8(const std::u32string_view str) {
+  std::string output;
+  for (const char32_t codepoint : str) {
+    CodepointToUtf8Append(codepoint, &output);
+  }
+  return output;
+}
+
 char32_t Util::Utf8ToCodepoint(const char *begin, const char *end,
                                size_t *mblen) {
   absl::string_view s(begin, end - begin);
@@ -470,6 +487,82 @@ bool Util::SplitLastChar32(absl::string_view s, absl::string_view *rest,
   return true;
 }
 
+bool Util::IsValidUtf8(absl::string_view s) {
+  char32_t first;
+  absl::string_view rest;
+  while (!s.empty()) {
+    if (!SplitFirstChar32(s, &first, &rest)) {
+      return false;
+    }
+    s = rest;
+  }
+  return true;
+}
+
+std::string Util::CodepointToUtf8(char32_t c) {
+  std::string output;
+  CodepointToUtf8Append(c, &output);
+  return output;
+}
+
+void Util::CodepointToUtf8Append(char32_t c, std::string *output) {
+  char buf[7];
+  output->append(buf, CodepointToUtf8(c, buf));
+}
+
+size_t Util::CodepointToUtf8(char32_t c, char *output) {
+  if (c == 0) {
+    // Do nothing if |c| is `\0`. Previous implementation of
+    // CodepointToUtf8Append worked like this.
+    output[0] = '\0';
+    return 0;
+  }
+  if (c < 0x00080) {
+    output[0] = static_cast<char>(c & 0xFF);
+    output[1] = '\0';
+    return 1;
+  }
+  if (c < 0x00800) {
+    output[0] = static_cast<char>(0xC0 + ((c >> 6) & 0x1F));
+    output[1] = static_cast<char>(0x80 + (c & 0x3F));
+    output[2] = '\0';
+    return 2;
+  }
+  if (c < 0x10000) {
+    output[0] = static_cast<char>(0xE0 + ((c >> 12) & 0x0F));
+    output[1] = static_cast<char>(0x80 + ((c >> 6) & 0x3F));
+    output[2] = static_cast<char>(0x80 + (c & 0x3F));
+    output[3] = '\0';
+    return 3;
+  }
+  if (c < 0x200000) {
+    output[0] = static_cast<char>(0xF0 + ((c >> 18) & 0x07));
+    output[1] = static_cast<char>(0x80 + ((c >> 12) & 0x3F));
+    output[2] = static_cast<char>(0x80 + ((c >> 6) & 0x3F));
+    output[3] = static_cast<char>(0x80 + (c & 0x3F));
+    output[4] = '\0';
+    return 4;
+  }
+  // below is not in UCS4 but in 32bit int.
+  if (c < 0x8000000) {
+    output[0] = static_cast<char>(0xF8 + ((c >> 24) & 0x03));
+    output[1] = static_cast<char>(0x80 + ((c >> 18) & 0x3F));
+    output[2] = static_cast<char>(0x80 + ((c >> 12) & 0x3F));
+    output[3] = static_cast<char>(0x80 + ((c >> 6) & 0x3F));
+    output[4] = static_cast<char>(0x80 + (c & 0x3F));
+    output[5] = '\0';
+    return 5;
+  }
+  output[0] = static_cast<char>(0xFC + ((c >> 30) & 0x01));
+  output[1] = static_cast<char>(0x80 + ((c >> 24) & 0x3F));
+  output[2] = static_cast<char>(0x80 + ((c >> 18) & 0x3F));
+  output[3] = static_cast<char>(0x80 + ((c >> 12) & 0x3F));
+  output[4] = static_cast<char>(0x80 + ((c >> 6) & 0x3F));
+  output[5] = static_cast<char>(0x80 + (c & 0x3F));
+  output[6] = '\0';
+  return 6;
+}
+
 absl::string_view Util::Utf8SubString(absl::string_view src, size_t start) {
   const char *begin = src.data();
   const char *end = begin + src.size();
diff --git a/src/base/util.h b/src/base/util.h
index a6199d813..1bd5d71e1 100644
--- a/src/base/util.h
+++ b/src/base/util.h
@@ -37,10 +37,7 @@
 #include <string_view>
 #include <vector>
 
-#include "absl/base/attributes.h"
-#include "absl/base/macros.h"
 #include "absl/strings/string_view.h"
-#include "base/strings/unicode.h"
 
 namespace mozc {
 
@@ -83,19 +80,12 @@ class Util {
   static bool IsCapitalizedAscii(absl::string_view s);
 
   // Returns the lengths of [src, src+size] encoded in UTF8.
-  ABSL_DEPRECATED("Use strings::CharsLen or AtLeastCharsLen.")
   static size_t CharsLen(absl::string_view str);
 
   // Converts a UTF-8 string to UTF-32.
-  ABSL_DEPRECATE_AND_INLINE()
-  static std::u32string Utf8ToUtf32(absl::string_view str) {
-    return strings::Utf8ToUtf32(str);
-  }
+  static std::u32string Utf8ToUtf32(absl::string_view str);
   // Converts a UTF-32 string to UTF-8.
-  ABSL_DEPRECATE_AND_INLINE()
-  static std::string Utf32ToUtf8(std::u32string_view str) {
-    return strings::Utf32ToUtf8(str);
-  }
+  static std::string Utf32ToUtf8(std::u32string_view str);
 
   // Converts the first character of UTF8 string starting at |begin| to UCS4.
   // The read byte length is stored to |mblen|.
@@ -107,16 +97,16 @@ class Util {
   }
 
   // Converts a UCS4 code point to UTF8 string.
-  ABSL_DEPRECATE_AND_INLINE() static std::string CodepointToUtf8(char32_t c) {
-    return strings::Char32ToUtf8(c);
-  }
+  static std::string CodepointToUtf8(char32_t c);
 
   // Converts a UCS4 code point to UTF8 string and appends it to |output|, i.e.,
   // |output| is not cleared.
-  ABSL_DEPRECATE_AND_INLINE()
-  static void CodepointToUtf8Append(char32_t c, std::string *output) {
-    return strings::StrAppendChar32(output, c);
-  }
+  static void CodepointToUtf8Append(char32_t c, std::string *output);
+
+  // Converts a UCS4 code point to UTF8 and stores it to char array.  The result
+  // is terminated by '\0'.  Returns the byte length of converted UTF8 string.
+  // REQUIRES: The output buffer must be longer than 7 bytes.
+  static size_t CodepointToUtf8(char32_t c, char *output);
 
   // Returns true if |s| is split into |first_char32| + |rest|.
   // You can pass nullptr to |first_char32| and/or |rest| to ignore the matched
@@ -135,23 +125,18 @@ class Util {
                               char32_t *last_char32);
 
   // Returns true if |s| is a valid UTF8.
-  ABSL_DEPRECATE_AND_INLINE() static bool IsValidUtf8(absl::string_view s) {
-    return strings::IsValidUtf8(s);
-  }
+  static bool IsValidUtf8(absl::string_view s);
 
   // Extracts a substring range, where both start and length are in terms of
   // UTF8 size. Note that the returned string view refers to the same memory
   // block as the input.
-  ABSL_DEPRECATED("Use strings::Utf8AsChars or strings::Utf8Substring instead.")
   static absl::string_view Utf8SubString(absl::string_view src, size_t start,
                                          size_t length);
   // This version extracts the substring to the end.
-  ABSL_DEPRECATED("Use strings::Utf8AsChars or strings::Utf8Substring instead.")
   static absl::string_view Utf8SubString(absl::string_view src, size_t start);
 
   // Extracts a substring of length |length| starting at |start|.
   // Note: |start| is the start position in UTF8, not byte position.
-  ABSL_DEPRECATED("Use strings::Utf8AsChars or strings::Utf8Substring instead.")
   static void Utf8SubString(absl::string_view src, size_t start, size_t length,
                             std::string *result);
 
@@ -274,7 +259,7 @@ class Util {
 //     char32_t c = iter.Get();
 //     ...
 //   }
-class ABSL_DEPRECATED("Use strings::Utf8AsChars instead.") ConstChar32Iterator {
+class ConstChar32Iterator {
  public:
   explicit ConstChar32Iterator(absl::string_view utf8_string);
   ConstChar32Iterator(const ConstChar32Iterator &) = delete;
diff --git a/src/base/util_test.cc b/src/base/util_test.cc
index 6bedf5c21..55079567b 100644
--- a/src/base/util_test.cc
+++ b/src/base/util_test.cc
@@ -326,8 +326,10 @@ TEST(UtilTest, Utf8ToCodepoint) {
 }
 
 TEST(UtilTest, CodepointToUtf8) {
+  // Do nothing if |c| is NUL. Previous implementation of CodepointToUtf8 worked
+  // like this even though the reason is unclear.
   std::string output = Util::CodepointToUtf8(0);
-  EXPECT_EQ(output, absl::string_view("\0", 1));
+  EXPECT_TRUE(output.empty());
 
   output = Util::CodepointToUtf8(0x7F);
   EXPECT_EQ(output, "\x7F");
@@ -342,7 +344,34 @@ TEST(UtilTest, CodepointToUtf8) {
   output = Util::CodepointToUtf8(0x10000);
   EXPECT_EQ(output, "\xF0\x90\x80\x80");
   output = Util::CodepointToUtf8(0x1FFFFF);
-  EXPECT_EQ(output, "\uFFFD");
+  EXPECT_EQ(output, "\xF7\xBF\xBF\xBF");
+
+  // Buffer version.
+  char buf[7];
+
+  EXPECT_EQ(Util::CodepointToUtf8(0, buf), 0);
+  EXPECT_EQ(strcmp(buf, ""), 0);
+
+  EXPECT_EQ(Util::CodepointToUtf8(0x7F, buf), 1);
+  EXPECT_EQ(strcmp("\x7F", buf), 0);
+
+  EXPECT_EQ(Util::CodepointToUtf8(0x80, buf), 2);
+  EXPECT_EQ(strcmp("\xC2\x80", buf), 0);
+
+  EXPECT_EQ(Util::CodepointToUtf8(0x7FF, buf), 2);
+  EXPECT_EQ(strcmp("\xDF\xBF", buf), 0);
+
+  EXPECT_EQ(Util::CodepointToUtf8(0x800, buf), 3);
+  EXPECT_EQ(strcmp("\xE0\xA0\x80", buf), 0);
+
+  EXPECT_EQ(Util::CodepointToUtf8(0xFFFF, buf), 3);
+  EXPECT_EQ(strcmp("\xEF\xBF\xBF", buf), 0);
+
+  EXPECT_EQ(Util::CodepointToUtf8(0x10000, buf), 4);
+  EXPECT_EQ(strcmp("\xF0\x90\x80\x80", buf), 0);
+
+  EXPECT_EQ(Util::CodepointToUtf8(0x1FFFFF, buf), 4);
+  EXPECT_EQ(strcmp("\xF7\xBF\xBF\xBF", buf), 0);
 }
 
 TEST(UtilTest, CharsLen) {
diff --git a/src/build_tools/BUILD.bazel b/src/build_tools/BUILD.bazel
index 8e57cc543..7b86c9bf1 100644
--- a/src/build_tools/BUILD.bazel
+++ b/src/build_tools/BUILD.bazel
@@ -179,3 +179,13 @@ bzl_library(
         "//bazel:run_build_tool_bzl",
     ],
 )
+
+exports_files([
+    "mozc_win32_resource_template.rc",
+])
+
+mozc_py_binary(
+    name = "gen_win32_resource_header",
+    srcs = ["gen_win32_resource_header.py"],
+    deps = [":mozc_version_lib"],
+)
diff --git a/src/build_tools/build_qt.py b/src/build_tools/build_qt.py
index f22a4f009..33d38c86b 100755
--- a/src/build_tools/build_qt.py
+++ b/src/build_tools/build_qt.py
@@ -37,7 +37,7 @@
 
 By default, this script assumes that Qt archives are stored as
 
-  src/third_party_cache/qtbase-everywhere-src-6.7.2.tar.xz
+  src/third_party_cache/qtbase-everywhere-src-6.7.3.tar.xz
 
 and Qt src files that are necessary to build Mozc will be checked out into
 
@@ -69,7 +69,7 @@
 ABS_QT_DEST_DIR = ABS_MOZC_SRC_DIR.joinpath('third_party', 'qt')
 # The archive filename should be consistent with update_deps.py.
 ABS_QT6_ARCHIVE_PATH = ABS_MOZC_SRC_DIR.joinpath(
-    'third_party_cache', 'qtbase-everywhere-src-6.7.2.tar.xz')
+    'third_party_cache', 'qtbase-everywhere-src-6.7.3.tar.xz')
 ABS_DEFAULT_NINJA_DIR = ABS_MOZC_SRC_DIR.joinpath('third_party', 'ninja')
 
 
diff --git a/src/build_tools/gen_win32_resource_header.py b/src/build_tools/gen_win32_resource_header.py
index d52bd41e8..c63343082 100755
--- a/src/build_tools/gen_win32_resource_header.py
+++ b/src/build_tools/gen_win32_resource_header.py
@@ -38,11 +38,12 @@
 
 
 import logging
-import mozc_version
 import optparse
 import os
 import sys
 
+from build_tools import mozc_version
+
 
 def ParseOptions():
   """Parse command line options.
@@ -55,6 +56,7 @@ def ParseOptions():
   parser.add_option('--output', dest='output')
   parser.add_option('--main', dest='main')
   parser.add_option('--template', dest='template')
+  parser.add_option('--utf8', action='store_true', dest='utf8', default=False)
 
   (options, unused_args) = parser.parse_args()
   return options
@@ -107,16 +109,17 @@ def main():
 
   version_definition = version.GetVersionInFormat(bootstrapper_template)
 
+  out_encoding = 'utf-8' if options.utf8 else 'utf-16le'
   old_content = ''
   if os.path.exists(options.output):
     # if the target file already exists, need to check the necessity of update.
     try:
-      old_content = open(options.output, encoding='utf-16le').read()
+      old_content = open(options.output, encoding=out_encoding).read()
     except UnicodeError:
       old_content = ''
 
   if version_definition != old_content:
-    open(options.output, 'w', encoding='utf-16le').write(version_definition)
+    open(options.output, 'w', encoding=out_encoding).write(version_definition)
 
 if __name__ == '__main__':
   main()
diff --git a/src/build_tools/update_deps.py b/src/build_tools/update_deps.py
index a279374c8..4d556bcda 100644
--- a/src/build_tools/update_deps.py
+++ b/src/build_tools/update_deps.py
@@ -81,9 +81,9 @@ def __hash__(self):
 
 
 QT6 = ArchiveInfo(
-    url='https://download.qt.io/archive/qt/6.7/6.7.2/submodules/qtbase-everywhere-src-6.7.2.tar.xz',
-    size=49364504,
-    sha256='c5f22a5e10fb162895ded7de0963328e7307611c688487b5d152c9ee64767599',
+    url='https://download.qt.io/archive/qt/6.7/6.7.3/submodules/qtbase-everywhere-src-6.7.3.tar.xz',
+    size=49426156,
+    sha256='8ccbb9ab055205ac76632c9eeddd1ed6fc66936fc56afc2ed0fd5d9e23da3097',
 )
 
 NINJA_MAC = ArchiveInfo(
diff --git a/src/converter/BUILD.bazel b/src/converter/BUILD.bazel
index bd227f17c..e48ae54c5 100644
--- a/src/converter/BUILD.bazel
+++ b/src/converter/BUILD.bazel
@@ -512,6 +512,7 @@ mozc_cc_test(
         ":segments",
         "//composer",
         "//composer:table",
+        "//config:config_handler",
         "//engine:engine_factory",
         "//engine:engine_interface",
         "//protocol:commands_cc_proto",
diff --git a/src/converter/converter_regression_test.cc b/src/converter/converter_regression_test.cc
index b80f63c59..5e9a2ab1e 100644
--- a/src/converter/converter_regression_test.cc
+++ b/src/converter/converter_regression_test.cc
@@ -32,6 +32,7 @@
 #include "absl/log/check.h"
 #include "composer/composer.h"
 #include "composer/table.h"
+#include "config/config_handler.h"
 #include "converter/converter_interface.h"
 #include "converter/segments.h"
 #include "engine/engine_factory.h"
@@ -68,12 +69,13 @@ TEST_F(ConverterRegressionTest, QueryOfDeathTest) {
   }
   {
     Segments segments;
-    ConversionRequest conv_request;
     // Create an empty composer.
     const Table table;
     const commands::Request request;
-    composer::Composer composer(&table, &request, nullptr);
-    conv_request.set_composer(&composer);
+    const commands::Context context;
+    const config::Config config = config::ConfigHandler::DefaultConfig();
+    composer::Composer composer(&table, &request, &config);
+    ConversionRequest conv_request(&composer, &request, &context, &config);
     // Converter returns false, but not crash.
     EXPECT_FALSE(converter->StartConversion(conv_request, &segments));
   }
diff --git a/src/data/images/win/BUILD.bazel b/src/data/images/win/BUILD.bazel
new file mode 100644
index 000000000..b5bc6a725
--- /dev/null
+++ b/src/data/images/win/BUILD.bazel
@@ -0,0 +1,44 @@
+# Copyright 2010-2021, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# Image files for Windows builds.
+
+package(default_visibility = ["//visibility:private"])
+
+filegroup(
+    name = "candidate_window_logo",
+    srcs = glob(["candidate_window_logo_*.bmp"]),
+    visibility = ["//renderer/win32:__subpackages__"],
+)
+
+filegroup(
+    name = "icons",
+    srcs = glob(["*.ico"]),
+    visibility = ["//win32/tip:__subpackages__"],
+)
diff --git a/src/prediction/dictionary_prediction_aggregator.cc b/src/prediction/dictionary_prediction_aggregator.cc
index 61134d931..f91691044 100644
--- a/src/prediction/dictionary_prediction_aggregator.cc
+++ b/src/prediction/dictionary_prediction_aggregator.cc
@@ -1706,6 +1706,8 @@ void DictionaryPredictionAggregator::AggregateTypingCorrectedPrediction(
   // insensitive dictionary lookup is also disabled as composition
   // spellchecker has already fixed them.
   ConversionRequest corrected_request = request;
+  // TODO(b/365909808): corrected_request.composer() returns nullptr. We should
+  // add an empty composer instead.
   corrected_request.set_composer(nullptr);
   corrected_request.set_kana_modifier_insensitive_conversion(false);
 
diff --git a/src/prediction/user_history_predictor_test.cc b/src/prediction/user_history_predictor_test.cc
index 84fd7d9ab..21589f22e 100644
--- a/src/prediction/user_history_predictor_test.cc
+++ b/src/prediction/user_history_predictor_test.cc
@@ -2788,7 +2788,7 @@ void InitSegmentsFromInputSequence(const absl::string_view text,
     composer->InsertCharacterKeyEvent(key);
   }
 
-  request->set_composer(composer);
+  ASSERT_EQ(&request->composer(), composer);
 
   request->set_request_type(ConversionRequest::PREDICTION);
   Segment *segment = segments->add_segment();
diff --git a/src/rewriter/BUILD.bazel b/src/rewriter/BUILD.bazel
index 4bd54711d..01b20fc89 100644
--- a/src/rewriter/BUILD.bazel
+++ b/src/rewriter/BUILD.bazel
@@ -1168,6 +1168,7 @@ mozc_cc_test(
         ":t13n_promotion_rewriter",
         ":transliteration_rewriter",
         "//composer",
+        "//config:config_handler",
         "//converter:segments",
         "//data_manager/testing:mock_data_manager",
         "//dictionary:pos_matcher",
diff --git a/src/rewriter/date_rewriter_test.cc b/src/rewriter/date_rewriter_test.cc
index 8b23e7b18..6782877f3 100644
--- a/src/rewriter/date_rewriter_test.cc
+++ b/src/rewriter/date_rewriter_test.cc
@@ -918,10 +918,10 @@ TEST_F(DateRewriterTest, NumberRewriterFromRawInputTest) {
   table.AddRule("222", "c", "");
   table.AddRule("3", "d", "");
   const commands::Request request;
+  const commands::Context context;
   const config::Config config;
   composer::Composer composer(&table, &request, &config);
-  ConversionRequest conversion_request;
-  conversion_request.set_composer(&composer);
+  ConversionRequest conversion_request(&composer, &request, &context, &config);
 
   // Key sequence : 2223
   // Preedit : cd
diff --git a/src/rewriter/rewriter_test.gyp b/src/rewriter/rewriter_test.gyp
index 16131b433..b3646a080 100644
--- a/src/rewriter/rewriter_test.gyp
+++ b/src/rewriter/rewriter_test.gyp
@@ -78,6 +78,7 @@
         '<(mozc_oss_src_dir)/base/base.gyp:number_util',
         '<(mozc_oss_src_dir)/base/base.gyp:serialized_string_array',
         '<(mozc_oss_src_dir)/base/base_test.gyp:clock_mock',
+        '<(mozc_oss_src_dir)/config/config.gyp:config_handler',
         '<(mozc_oss_src_dir)/converter/converter.gyp:converter',
         '<(mozc_oss_src_dir)/data_manager/testing/mock_data_manager.gyp:mock_data_manager',
         '<(mozc_oss_src_dir)/dictionary/dictionary_base.gyp:user_pos',
diff --git a/src/rewriter/t13n_promotion_rewriter_test.cc b/src/rewriter/t13n_promotion_rewriter_test.cc
index 0649b4214..033f8d8d4 100644
--- a/src/rewriter/t13n_promotion_rewriter_test.cc
+++ b/src/rewriter/t13n_promotion_rewriter_test.cc
@@ -35,6 +35,7 @@
 
 #include "absl/strings/string_view.h"
 #include "composer/composer.h"
+#include "config/config_handler.h"
 #include "converter/segments.h"
 #include "data_manager/testing/mock_data_manager.h"
 #include "dictionary/pos_matcher.h"
@@ -75,12 +76,15 @@ class T13nPromotionRewriterTest : public testing::TestWithTempUserProfile {
     t13n_rewriter_ = std::make_unique<TransliterationRewriter>(
         dictionary::PosMatcher(mock_data_manager_.GetPosMatcherData()));
 
-    mobile_conv_request_ = ConversionRequest();
     composer_ = composer::Composer();
     mobile_request_ = commands::Request();
 
     request_test_util::FillMobileRequest(&mobile_request_);
     composer_.SetRequest(&mobile_request_);
+
+    mobile_conv_request_ =
+        ConversionRequest(&composer_, &mobile_request_, &context_,
+                          &config::ConfigHandler::DefaultConfig());
     mobile_conv_request_.set_request(&mobile_request_);
     mobile_conv_request_.set_composer(&composer_);
   }
@@ -88,6 +92,7 @@ class T13nPromotionRewriterTest : public testing::TestWithTempUserProfile {
   std::unique_ptr<TransliterationRewriter> t13n_rewriter_;
   ConversionRequest mobile_conv_request_;
   composer::Composer composer_;
+  commands::Context context_;
   commands::Request mobile_request_;
 
  private: