diff --git a/server/CMakeLists.txt b/server/CMakeLists.txt
index 3b91db96..abd9a9be 100644
--- a/server/CMakeLists.txt
+++ b/server/CMakeLists.txt
@@ -84,6 +84,7 @@ set(SRC_FILES
 )
 
 set(SRC_FILES_IME_ENGINE
+    "./MetasequoiaImeEngine/common/helpcode_utils.cpp"
     "./MetasequoiaImeEngine/common/string_utils.cpp"
     "./MetasequoiaImeEngine/core/ime_session.cpp"
     "./MetasequoiaImeEngine/providers/provider_registry.cpp"
diff --git a/server/MetasequoiaImeEngine b/server/MetasequoiaImeEngine
index 964b6940..0f2afad9 160000
--- a/server/MetasequoiaImeEngine
+++ b/server/MetasequoiaImeEngine
@@ -1 +1 @@
-Subproject commit 964b6940a6c1d64416884e3327f48d3d44b902e0
+Subproject commit 0f2afad94dfc77c602f61aba19ba45af07241ed1
diff --git a/server/src/ipc/event_listener.cpp b/server/src/ipc/event_listener.cpp
index 04e8b664..b9710efd 100644
--- a/server/src/ipc/event_listener.cpp
+++ b/server/src/ipc/event_listener.cpp
@@ -19,7 +19,7 @@
 #include "fmt/xchar.h"
 #include <utf8.h>
 #include "global/globals.h"
-#include "MetasequoiaImeEngine/shuangpin/shuangpin_utils.h"
+#include "MetasequoiaImeEngine/common/helpcode_utils.h"
 #include "ipc/event_listener.h"
 #include "utils/ime_utils.h"
 #include "cloud/cloud_ime.h"
@@ -61,7 +61,7 @@ std::string BuildCurrentCandidatePage()
             ui.selected_text = string_to_wstring(word);
         }
 
-        candidate_string += word + ShuangpinUtil::compute_helpcodes(word);
+        candidate_string += word + HelpcodeUtils::compute_helpcodes(word);
         maxCount = std::max(maxCount, static_cast<int>(utf8::distance(word.begin(), word.end())));
         ui.page_words.push_back(string_to_wstring(word));
         if (i < loop - 1)
diff --git a/server/src/session/engine_input_session.cpp b/server/src/session/engine_input_session.cpp
index c4d15d6b..f446d49e 100644
--- a/server/src/session/engine_input_session.cpp
+++ b/server/src/session/engine_input_session.cpp
@@ -2,6 +2,7 @@
 
 #include <algorithm>
 #include "config/ime_config.h"
+#include "MetasequoiaImeEngine/common/helpcode_utils.h"
 #include "MetasequoiaImeEngine/shuangpin/shuangpin_query.h"
 #include "MetasequoiaImeEngine/shuangpin/shuangpin_utils.h"
 
@@ -126,6 +127,10 @@ std::string EngineInputSession::get_pinyin_segmentation_with_cases() const
     {
         return request().raw_segmentation.empty() ? request().raw_input : request().raw_segmentation;
     }
+    if (current_scheme_type() == SchemeType::Quanpin)
+    {
+        return request().raw_segmentation.empty() ? request().raw_input_with_cases : request().raw_segmentation;
+    }
     return request().normalized_segmentation.empty() ? request().segmentation : request().normalized_segmentation;
 }
 
@@ -198,7 +203,7 @@ IInputSession::SelectionTransition EngineInputSession::advance_composition_after
     if (is_shuangpin())
     {
         const auto base = ResolveShuangpinCompositionBase(request());
-        const size_t word_pinyin_length = ShuangpinUtil::cnt_han_chars(selected_word) * 2;
+        const size_t word_pinyin_length = HelpcodeUtils::count_han_chars(selected_word) * 2;
         const size_t total_input_length = base.raw_input.size();
 
         transition.full_pure_pinyin =
@@ -296,7 +301,7 @@ EngineInputSession::update_creating_word_progress(const std::string &current_pin
     progress.word = current_word + selected_word;
     progress.preedit = progress.word + selection_transition.current_segmentation;
     progress.completed =
-        is_shuangpin() ? ShuangpinUtil::cnt_han_chars(progress.word) * 2 == progress.pinyin.size() : false;
+        is_shuangpin() ? HelpcodeUtils::count_han_chars(progress.word) * 2 == progress.pinyin.size() : false;
     return progress;
 }
 
diff --git a/server/src/session/shuangpin_input_session.cpp b/server/src/session/shuangpin_input_session.cpp
index 9594654d..c0bbb02c 100644
--- a/server/src/session/shuangpin_input_session.cpp
+++ b/server/src/session/shuangpin_input_session.cpp
@@ -1,5 +1,5 @@
 #include "shuangpin_input_session.h"
-#include "MetasequoiaImeEngine/shuangpin/shuangpin_utils.h"
+#include "MetasequoiaImeEngine/common/helpcode_utils.h"
 #include <stdexcept>
 
 ShuangpinInputSession::ShuangpinInputSession() : dictionary_(std::make_unique<DictionaryUlPb>())
@@ -169,6 +169,6 @@ ShuangpinInputSession::update_creating_word_progress(const std::string &current_
     progress.pinyin = current_pinyin.empty() ? selection_transition.full_pure_pinyin : current_pinyin;
     progress.word = current_word + selected_word;
     progress.preedit = progress.word + selection_transition.current_segmentation;
-    progress.completed = ShuangpinUtil::cnt_han_chars(progress.word) * 2 == progress.pinyin.size();
+    progress.completed = HelpcodeUtils::count_han_chars(progress.word) * 2 == progress.pinyin.size();
     return progress;
 }
diff --git a/server/tests/CMakeLists.txt b/server/tests/CMakeLists.txt
index 18747a3a..bf21aa52 100644
--- a/server/tests/CMakeLists.txt
+++ b/server/tests/CMakeLists.txt
@@ -9,6 +9,7 @@ set(TEST_SOURCE_FILES
     "${CMAKE_SOURCE_DIR}/src/config/ime_config.cpp"
     "${CMAKE_SOURCE_DIR}/src/session/engine_input_session.cpp"
     "${CMAKE_SOURCE_DIR}/src/utils/common_utils.cpp"
+    "${CMAKE_SOURCE_DIR}/MetasequoiaImeEngine/common/helpcode_utils.cpp"
     "${CMAKE_SOURCE_DIR}/MetasequoiaImeEngine/core/ime_session.cpp"
     "${CMAKE_SOURCE_DIR}/MetasequoiaImeEngine/common/string_utils.cpp"
     "${CMAKE_SOURCE_DIR}/MetasequoiaImeEngine/providers/provider_registry.cpp"
diff --git a/server/tests/src/test_quanpin_scheme.cpp b/server/tests/src/test_quanpin_scheme.cpp
index cc1c0f52..34076e78 100644
--- a/server/tests/src/test_quanpin_scheme.cpp
+++ b/server/tests/src/test_quanpin_scheme.cpp
@@ -1,4 +1,5 @@
 #include "tests/includes/test_framework.h"
+#include "MetasequoiaImeEngine/common/helpcode_utils.h"
 #include "MetasequoiaImeEngine/schemes/quanpin_scheme.h"
 
 namespace
@@ -34,3 +35,56 @@ TEST_CASE(QuanpinSchemeApostropheIsPreservedInRawInput)
     REQUIRE_EQ(request.raw_input, std::string("x'i"));
     REQUIRE_EQ(request.normalized_input, std::string("xi"));
 }
+
+TEST_CASE(QuanpinSchemePreservesUppercaseRawInputForHelpcodes)
+{
+    QuanpinScheme scheme;
+    InputKey(scheme, 'X', L'x');
+    InputKey(scheme, 'I', L'i');
+    InputKey(scheme, 'T', L't');
+    InputKey(scheme, 'E', L'e');
+    InputKey(scheme, 'L', L'l');
+    InputKey(scheme, 'E', L'e');
+    InputKey(scheme, 'A', L'A', 1);
+    InputKey(scheme, 'A', L'A', 1);
+
+    const QueryRequest request = scheme.build_request();
+    REQUIRE(request.valid);
+    REQUIRE_EQ(request.raw_input_with_cases, std::string("xiteleAA"));
+    REQUIRE_EQ(request.raw_input, std::string("xiteleaa"));
+    REQUIRE_EQ(request.normalized_input, std::string("xitele"));
+    REQUIRE_EQ(request.raw_segmentation, std::string("xi'te'le'AA"));
+}
+
+TEST_CASE(QuanpinDoubleHelpModeRecognizesTrailingUppercaseLetters)
+{
+    REQUIRE(HelpcodeUtils::is_quanpin_double_help_mode("xiteleAA"));
+    REQUIRE(!HelpcodeUtils::is_quanpin_double_help_mode("xiteleaA"));
+    REQUIRE(!HelpcodeUtils::is_quanpin_double_help_mode("xiteleaa"));
+}
+
+TEST_CASE(QuanpinSchemePreservesUppercaseRawInputForSingleHelpcode)
+{
+    QuanpinScheme scheme;
+    InputKey(scheme, 'X', L'x');
+    InputKey(scheme, 'I', L'i');
+    InputKey(scheme, 'T', L't');
+    InputKey(scheme, 'E', L'e');
+    InputKey(scheme, 'L', L'l');
+    InputKey(scheme, 'E', L'e');
+    InputKey(scheme, 'A', L'A', 1);
+
+    const QueryRequest request = scheme.build_request();
+    REQUIRE(request.valid);
+    REQUIRE_EQ(request.raw_input_with_cases, std::string("xiteleA"));
+    REQUIRE_EQ(request.raw_input, std::string("xitelea"));
+    REQUIRE_EQ(request.normalized_input, std::string("xitele"));
+    REQUIRE_EQ(request.raw_segmentation, std::string("xi'te'le'A"));
+}
+
+TEST_CASE(QuanpinSingleHelpModeRecognizesTrailingUppercaseLetter)
+{
+    REQUIRE(HelpcodeUtils::is_quanpin_single_help_mode("xiteleA"));
+    REQUIRE(!HelpcodeUtils::is_quanpin_single_help_mode("xiteleAA"));
+    REQUIRE(!HelpcodeUtils::is_quanpin_single_help_mode("xitelea"));
+}