diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -28,6 +28,7 @@
 add_subdirectory(gtkproxies)
 add_subdirectory(gtk3proxies)
 add_subdirectory(kded)
+add_subdirectory(kconf_update)
 
 # add clang-format target for all our real source files
 file(GLOB_RECURSE ALL_CLANG_FORMAT_SOURCE_FILES *.cpp *.h)
diff --git a/kconf_update/CMakeLists.txt b/kconf_update/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/kconf_update/CMakeLists.txt
@@ -0,0 +1,38 @@
+add_executable(gtk_theme gtktheme.cpp)
+
+target_sources(gtk_theme
+  PRIVATE
+    ../kded/configeditor.cpp
+)
+
+target_link_libraries(gtk_theme
+  PRIVATE
+    Qt5::Core
+    KF5::ConfigCore
+    ${GIO2_LIBRARY}
+    ${GOBJECT2_LIBRARY}
+)
+
+target_include_directories(gtk_theme
+  PRIVATE
+    ../kded/
+    ${GTK3_INCLUDE_DIRS}
+)
+
+target_compile_definitions(gtk_theme
+  PRIVATE
+    QT_NO_SIGNALS_SLOTS_KEYWORDS
+)
+
+install(
+  TARGETS
+    gtk_theme
+  DESTINATION
+    ${LIB_INSTALL_DIR}/kconf_update_bin/
+)
+install(
+  FILES
+    gtkconfig.upd
+  DESTINATION
+    ${KCONF_UPDATE_INSTALL_DIR}
+)
diff --git a/kconf_update/gtkconfig.upd b/kconf_update/gtkconfig.upd
new file mode 100644
--- /dev/null
+++ b/kconf_update/gtkconfig.upd
@@ -0,0 +1,3 @@
+Version=5
+Id=gtk_theme
+Script=gtk_theme
diff --git a/kconf_update/gtktheme.cpp b/kconf_update/gtktheme.cpp
new file mode 100644
--- /dev/null
+++ b/kconf_update/gtktheme.cpp
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2020 Mikhail Zolotukhin <zomial@protonmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License or (at your option) version 3 or any later version
+ * accepted by the membership of KDE e.V. (or its successor approved
+ * by the membership of KDE e.V.), which shall act as a proxy
+ * defined in Section 14 of version 3 of the license.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <QString>
+
+#include "configeditor.h"
+
+void upgradeGtk2Theme();
+void upgradeGtk3Theme();
+
+int main() {
+    upgradeGtk2Theme();
+    upgradeGtk3Theme();
+    return 0;
+}
+
+void upgradeGtk2Theme() {
+    QString currentGtk2Theme = ConfigEditor::gtk2ConfigValue(QStringLiteral("gtk-theme-name"));
+    if (currentGtk2Theme.isEmpty()
+     || currentGtk2Theme == QStringLiteral("oxygen-gtk")
+     || currentGtk2Theme == QStringLiteral("BreezyGTK")
+     || currentGtk2Theme == QStringLiteral("Orion")
+    ) {
+        ConfigEditor::setGtk2ConfigValue(QStringLiteral("gtk-theme-name"), QStringLiteral("Breeze"));
+    }
+}
+
+void upgradeGtk3Theme() {
+    QString currentGtk3Theme = ConfigEditor::gtk3ConfigValueSettingsIni(QStringLiteral("gtk-theme-name"));
+    if (currentGtk3Theme.isEmpty()
+     || currentGtk3Theme == QStringLiteral("oxygen-gtk")
+     || currentGtk3Theme == QStringLiteral("BreezyGTK")
+     || currentGtk3Theme == QStringLiteral("Orion")
+    ) {
+        ConfigEditor::setGtk3ConfigValueDconf(QStringLiteral("gtk-theme"), QStringLiteral("Breeze"));
+        ConfigEditor::setGtk3ConfigValueSettingsIni(QStringLiteral("gtk-theme-name"), QStringLiteral("Breeze"));
+        ConfigEditor::setGtk3ConfigValueXSettingsd(QStringLiteral("Net/ThemeName"),  QStringLiteral("Breeze"));
+    }
+}
diff --git a/kded/configeditor.cpp b/kded/configeditor.cpp
--- a/kded/configeditor.cpp
+++ b/kded/configeditor.cpp
@@ -109,7 +109,7 @@
         }
     }
 
-    return QStringLiteral("Breeze");
+    return QString();
 }
 
 QString ConfigEditor::gtk3ConfigValueSettingsIni(const QString& paramName)
@@ -120,7 +120,7 @@
     KSharedConfig::Ptr gtk3Config = KSharedConfig::openConfig(gtk3ConfigPath, KConfig::NoGlobals);
     KConfigGroup group = gtk3Config->group(QStringLiteral("Settings"));
 
-    return group.readEntry(paramName, QStringLiteral("Breeze"));
+    return group.readEntry(paramName);
 }