diff --git a/Source/Core/DolphinQt/Config/GameConfigWidget.cpp b/Source/Core/DolphinQt/Config/GameConfigWidget.cpp
index ce56a357be..f8e0392e61 100644
--- a/Source/Core/DolphinQt/Config/GameConfigWidget.cpp
+++ b/Source/Core/DolphinQt/Config/GameConfigWidget.cpp
@@ -213,7 +213,7 @@ void GameConfigWidget::ConnectWidgets()
   for (QCheckBox* box :
        {m_enable_dual_core, m_enable_mmu, m_enable_fprf, m_sync_gpu, m_emulate_disc_speed,
         m_use_dsp_hle, m_manual_texture_sampling, m_use_monoscopic_shadows})
-    connect(box, &QCheckBox::stateChanged, this, &GameConfigWidget::SaveSettings);
+    connect(box, &QCheckBox::checkStateChanged, this, &GameConfigWidget::SaveSettings);
 
   connect(m_deterministic_dual_core, &QComboBox::currentIndexChanged, this,
           &GameConfigWidget::SaveSettings);
diff --git a/Source/Core/DolphinQt/Config/Graphics/HacksWidget.cpp b/Source/Core/DolphinQt/Config/Graphics/HacksWidget.cpp
index 19712e38f8..83d218cc72 100644
--- a/Source/Core/DolphinQt/Config/Graphics/HacksWidget.cpp
+++ b/Source/Core/DolphinQt/Config/Graphics/HacksWidget.cpp
@@ -148,13 +148,13 @@ void HacksWidget::OnBackendChanged(const QString& backend_name)
 void HacksWidget::ConnectWidgets()
 {
   connect(m_accuracy, &QSlider::valueChanged, [this](int) { SaveSettings(); });
-  connect(m_store_efb_copies, &QCheckBox::stateChanged,
+  connect(m_store_efb_copies, &QCheckBox::checkStateChanged,
           [this](int) { UpdateDeferEFBCopiesEnabled(); });
-  connect(m_store_xfb_copies, &QCheckBox::stateChanged,
+  connect(m_store_xfb_copies, &QCheckBox::checkStateChanged,
           [this](int) { UpdateDeferEFBCopiesEnabled(); });
-  connect(m_immediate_xfb, &QCheckBox::stateChanged,
+  connect(m_immediate_xfb, &QCheckBox::checkStateChanged,
           [this](int) { UpdateSkipPresentingDuplicateFramesEnabled(); });
-  connect(m_vi_skip, &QCheckBox::stateChanged,
+  connect(m_vi_skip, &QCheckBox::checkStateChanged,
           [this](int) { UpdateSkipPresentingDuplicateFramesEnabled(); });
 }
 
diff --git a/Source/Core/DolphinQt/Config/Mapping/MappingNumeric.cpp b/Source/Core/DolphinQt/Config/Mapping/MappingNumeric.cpp
index 9a98716270..5fa518ea61 100644
--- a/Source/Core/DolphinQt/Config/Mapping/MappingNumeric.cpp
+++ b/Source/Core/DolphinQt/Config/Mapping/MappingNumeric.cpp
@@ -76,7 +76,7 @@ MappingBool::MappingBool(MappingWidget* parent, ControllerEmu::NumericSetting<bo
   if (const auto ui_description = m_setting.GetUIDescription())
     setToolTip(tr(ui_description));
 
-  connect(this, &QCheckBox::stateChanged, this, [this, parent](int value) {
+  connect(this, &QCheckBox::checkStateChanged, this, [this, parent](Qt::CheckState value) {
     m_setting.SetValue(value != 0);
     ConfigChanged();
     parent->SaveSettings();
diff --git a/Source/Core/DolphinQt/Config/VerifyWidget.cpp b/Source/Core/DolphinQt/Config/VerifyWidget.cpp
index 7c976092b1..09b3c25036 100644
--- a/Source/Core/DolphinQt/Config/VerifyWidget.cpp
+++ b/Source/Core/DolphinQt/Config/VerifyWidget.cpp
@@ -121,8 +121,8 @@ void VerifyWidget::ConnectWidgets()
 {
   connect(m_verify_button, &QPushButton::clicked, this, &VerifyWidget::Verify);
 
-  connect(m_md5_checkbox, &QCheckBox::stateChanged, this, &VerifyWidget::UpdateRedumpEnabled);
-  connect(m_sha1_checkbox, &QCheckBox::stateChanged, this, &VerifyWidget::UpdateRedumpEnabled);
+  connect(m_md5_checkbox, &QCheckBox::checkStateChanged, this, &VerifyWidget::UpdateRedumpEnabled);
+  connect(m_sha1_checkbox, &QCheckBox::checkStateChanged, this, &VerifyWidget::UpdateRedumpEnabled);
 }
 
 static void SetHash(QLineEdit* line_edit, const std::vector<u8>& hash)
diff --git a/Source/Core/DolphinQt/Debugger/NetworkWidget.cpp b/Source/Core/DolphinQt/Debugger/NetworkWidget.cpp
index e5b91e856a..775d30d32c 100644
--- a/Source/Core/DolphinQt/Debugger/NetworkWidget.cpp
+++ b/Source/Core/DolphinQt/Debugger/NetworkWidget.cpp
@@ -209,22 +209,22 @@ void NetworkWidget::ConnectWidgets()
 {
   connect(m_dump_format_combo, &QComboBox::currentIndexChanged, this,
           &NetworkWidget::OnDumpFormatComboChanged);
-  connect(m_dump_ssl_read_checkbox, &QCheckBox::stateChanged, [](int state) {
+  connect(m_dump_ssl_read_checkbox, &QCheckBox::checkStateChanged, [](Qt::CheckState state) {
     Config::SetBaseOrCurrent(Config::MAIN_NETWORK_SSL_DUMP_READ, state == Qt::Checked);
   });
-  connect(m_dump_ssl_write_checkbox, &QCheckBox::stateChanged, [](int state) {
+  connect(m_dump_ssl_write_checkbox, &QCheckBox::checkStateChanged, [](Qt::CheckState state) {
     Config::SetBaseOrCurrent(Config::MAIN_NETWORK_SSL_DUMP_WRITE, state == Qt::Checked);
   });
-  connect(m_dump_root_ca_checkbox, &QCheckBox::stateChanged, [](int state) {
+  connect(m_dump_root_ca_checkbox, &QCheckBox::checkStateChanged, [](Qt::CheckState state) {
     Config::SetBaseOrCurrent(Config::MAIN_NETWORK_SSL_DUMP_ROOT_CA, state == Qt::Checked);
   });
-  connect(m_dump_peer_cert_checkbox, &QCheckBox::stateChanged, [](int state) {
+  connect(m_dump_peer_cert_checkbox, &QCheckBox::checkStateChanged, [](Qt::CheckState state) {
     Config::SetBaseOrCurrent(Config::MAIN_NETWORK_SSL_DUMP_PEER_CERT, state == Qt::Checked);
   });
-  connect(m_verify_certificates_checkbox, &QCheckBox::stateChanged, [](int state) {
+  connect(m_verify_certificates_checkbox, &QCheckBox::checkStateChanged, [](Qt::CheckState state) {
     Config::SetBaseOrCurrent(Config::MAIN_NETWORK_SSL_VERIFY_CERTIFICATES, state == Qt::Checked);
   });
-  connect(m_dump_bba_checkbox, &QCheckBox::stateChanged, [](int state) {
+  connect(m_dump_bba_checkbox, &QCheckBox::checkStateChanged, [](Qt::CheckState state) {
     Config::SetBaseOrCurrent(Config::MAIN_NETWORK_DUMP_BBA, state == Qt::Checked);
   });
   connect(m_open_dump_folder, &QPushButton::clicked, [] {
diff --git a/Source/Core/DolphinQt/NKitWarningDialog.cpp b/Source/Core/DolphinQt/NKitWarningDialog.cpp
index 6c1bd5b117..a7d299600b 100644
--- a/Source/Core/DolphinQt/NKitWarningDialog.cpp
+++ b/Source/Core/DolphinQt/NKitWarningDialog.cpp
@@ -80,7 +80,7 @@ NKitWarningDialog::NKitWarningDialog(QWidget* parent) : QDialog(parent)
   connect(cancel, &QPushButton::clicked, this, &QDialog::reject);
 
   ok->setEnabled(false);
-  connect(checkbox_accept, &QCheckBox::stateChanged,
+  connect(checkbox_accept, &QCheckBox::checkStateChanged,
           [ok](int state) { ok->setEnabled(state == Qt::Checked); });
 
   connect(this, &QDialog::accepted, [checkbox_skip] {
diff --git a/Source/Core/DolphinQt/NetPlay/NetPlaySetupDialog.cpp b/Source/Core/DolphinQt/NetPlay/NetPlaySetupDialog.cpp
index f99a493a77..df7060b6c4 100644
--- a/Source/Core/DolphinQt/NetPlay/NetPlaySetupDialog.cpp
+++ b/Source/Core/DolphinQt/NetPlay/NetPlaySetupDialog.cpp
@@ -243,7 +243,7 @@ void NetPlaySetupDialog::ConnectWidgets()
           &NetPlaySetupDialog::SaveSettings);
 
 #ifdef USE_UPNP
-  connect(m_host_upnp, &QCheckBox::stateChanged, this, &NetPlaySetupDialog::SaveSettings);
+  connect(m_host_upnp, &QCheckBox::checkStateChanged, this, &NetPlaySetupDialog::SaveSettings);
 #endif
 
   connect(m_connect_button, &QPushButton::clicked, this, &QDialog::accept);
diff --git a/Source/Core/DolphinQt/NetPlay/PadMappingDialog.cpp b/Source/Core/DolphinQt/NetPlay/PadMappingDialog.cpp
index 35946d8f6d..63c852368d 100644
--- a/Source/Core/DolphinQt/NetPlay/PadMappingDialog.cpp
+++ b/Source/Core/DolphinQt/NetPlay/PadMappingDialog.cpp
@@ -61,7 +61,7 @@ void PadMappingDialog::ConnectWidgets()
   }
   for (const auto& checkbox : m_gba_boxes)
   {
-    connect(checkbox, &QCheckBox::stateChanged, this, &PadMappingDialog::OnMappingChanged);
+    connect(checkbox, &QCheckBox::checkStateChanged, this, &PadMappingDialog::OnMappingChanged);
   }
 }
 
diff --git a/Source/Core/DolphinQt/Settings/AdvancedPane.cpp b/Source/Core/DolphinQt/Settings/AdvancedPane.cpp
index e15b8f2325..857ea87c5b 100644
--- a/Source/Core/DolphinQt/Settings/AdvancedPane.cpp
+++ b/Source/Core/DolphinQt/Settings/AdvancedPane.cpp
@@ -13,6 +13,7 @@
 #include <QRadioButton>
 #include <QSignalBlocker>
 #include <QSlider>
+#include <QTimeZone>
 #include <QVBoxLayout>
 #include <cmath>
 
@@ -170,9 +171,9 @@ void AdvancedPane::CreateLayout()
       QStringLiteral("mm"), QStringLiteral("mm:ss")));
 
   QtUtils::ShowFourDigitYear(m_custom_rtc_datetime);
-  m_custom_rtc_datetime->setDateTimeRange(QDateTime({2000, 1, 1}, {0, 0, 0}, Qt::UTC),
-                                          QDateTime({2099, 12, 31}, {23, 59, 59}, Qt::UTC));
-  m_custom_rtc_datetime->setTimeSpec(Qt::UTC);
+  m_custom_rtc_datetime->setDateTimeRange(QDateTime({2000, 1, 1}, {0, 0, 0}, QTimeZone::UTC),
+                                          QDateTime({2099, 12, 31}, {23, 59, 59}, QTimeZone::UTC));
+  m_custom_rtc_datetime->setTimeZone(QTimeZone::UTC);
   rtc_options->layout()->addWidget(m_custom_rtc_datetime);
 
   auto* custom_rtc_description =
diff --git a/Source/Core/DolphinQt/Settings/GameCubePane.cpp b/Source/Core/DolphinQt/Settings/GameCubePane.cpp
index 806e0c7840..e40aa8a1dd 100644
--- a/Source/Core/DolphinQt/Settings/GameCubePane.cpp
+++ b/Source/Core/DolphinQt/Settings/GameCubePane.cpp
@@ -247,7 +247,7 @@ void GameCubePane::CreateWidgets()
 void GameCubePane::ConnectWidgets()
 {
   // IPL Settings
-  connect(m_skip_main_menu, &QCheckBox::stateChanged, this, &GameCubePane::SaveSettings);
+  connect(m_skip_main_menu, &QCheckBox::checkStateChanged, this, &GameCubePane::SaveSettings);
   connect(m_language_combo, &QComboBox::currentIndexChanged, this, &GameCubePane::SaveSettings);
 
   // Device Settings
@@ -278,10 +278,10 @@ void GameCubePane::ConnectWidgets()
 
 #ifdef HAS_LIBMGBA
   // GBA Settings
-  connect(m_gba_threads, &QCheckBox::stateChanged, this, &GameCubePane::SaveSettings);
+  connect(m_gba_threads, &QCheckBox::checkStateChanged, this, &GameCubePane::SaveSettings);
   connect(m_gba_bios_edit, &QLineEdit::editingFinished, this, &GameCubePane::SaveSettings);
   connect(m_gba_browse_bios, &QPushButton::clicked, this, &GameCubePane::BrowseGBABios);
-  connect(m_gba_save_rom_path, &QCheckBox::stateChanged, this, &GameCubePane::SaveRomPathChanged);
+  connect(m_gba_save_rom_path, &QCheckBox::checkStateChanged, this, &GameCubePane::SaveRomPathChanged);
   connect(m_gba_saves_edit, &QLineEdit::editingFinished, this, &GameCubePane::SaveSettings);
   connect(m_gba_browse_saves, &QPushButton::clicked, this, &GameCubePane::BrowseGBASaves);
   for (size_t i = 0; i < m_gba_browse_roms.size(); ++i)
diff --git a/Source/Core/DolphinQt/TAS/TASCheckBox.cpp b/Source/Core/DolphinQt/TAS/TASCheckBox.cpp
index 3e7f998339..727d065d64 100644
--- a/Source/Core/DolphinQt/TAS/TASCheckBox.cpp
+++ b/Source/Core/DolphinQt/TAS/TASCheckBox.cpp
@@ -15,7 +15,7 @@ TASCheckBox::TASCheckBox(const QString& text, TASInputWindow* parent)
 {
   setTristate(true);
 
-  connect(this, &TASCheckBox::stateChanged, this, &TASCheckBox::OnUIValueChanged);
+  connect(this, &TASCheckBox::checkStateChanged, this, &TASCheckBox::OnUIValueChanged);
 }
 
 bool TASCheckBox::GetValue() const
@@ -58,7 +58,7 @@ void TASCheckBox::mousePressEvent(QMouseEvent* event)
   setCheckState(Qt::PartiallyChecked);
 }
 
-void TASCheckBox::OnUIValueChanged(int new_value)
+void TASCheckBox::OnUIValueChanged(Qt::CheckState new_value)
 {
   m_state.OnUIValueChanged(new_value);
 }
diff --git a/Source/Core/DolphinQt/TAS/TASCheckBox.h b/Source/Core/DolphinQt/TAS/TASCheckBox.h
index 3af68d43b2..c7d4e0ff67 100644
--- a/Source/Core/DolphinQt/TAS/TASCheckBox.h
+++ b/Source/Core/DolphinQt/TAS/TASCheckBox.h
@@ -25,7 +25,7 @@ protected:
   void mousePressEvent(QMouseEvent* event) override;
 
 private slots:
-  void OnUIValueChanged(int new_value);
+  void OnUIValueChanged(Qt::CheckState new_value);
   void ApplyControllerValueChange();
 
 private: