diff --git a/src/plugins/designer/formwindowfile.cpp b/src/plugins/designer/formwindowfile.cpp
index c4b59131e53..aab54d96313 100644
--- a/src/plugins/designer/formwindowfile.cpp
+++ b/src/plugins/designer/formwindowfile.cpp
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
 
 #include "formwindowfile.h"
+#include "qtcreatorintegration.h"
 #include "designerconstants.h"
 #include "resourcehandler.h"
 
@@ -230,6 +231,10 @@ bool FormWindowFile::writeFile(const Utils::FilePath &filePath, QString *errorSt
 {
     if (Designer::Constants::Internal::debug)
         qDebug() << Q_FUNC_INFO << this->filePath() << filePath;
+    auto *integration = qobject_cast<QtCreatorIntegration *>(m_formWindow->core()->integration());
+    Q_ASSERT(integration);
+    if (!integration->setQtVersionFromFile(filePath))
+        integration->resetQtVersion();
     return write(filePath, format(), m_formWindow->contents(), errorString);
 }
 
diff --git a/src/plugins/designer/qtcreatorintegration.cpp b/src/plugins/designer/qtcreatorintegration.cpp
index 5e6d8900959..d0b80e66360 100644
--- a/src/plugins/designer/qtcreatorintegration.cpp
+++ b/src/plugins/designer/qtcreatorintegration.cpp
@@ -37,6 +37,8 @@
 #include <texteditor/texteditor.h>
 #include <texteditor/textdocument.h>
 
+#include <qtsupport/qtkitaspect.h>
+
 #include <utils/algorithm.h>
 #include <utils/mimeutils.h>
 #include <utils/qtcassert.h>
@@ -44,16 +46,20 @@
 #include <utils/temporaryfile.h>
 
 #include <QDesignerFormWindowInterface>
+#include <QDesignerFormWindowManagerInterface>
 #include <QDesignerFormEditorInterface>
 #include <QDebug>
 #include <QDir>
 #include <QFileInfo>
+#include <QLibraryInfo>
 #include <QLoggingCategory>
 #include <QMessageBox>
 #include <QHash>
+#include <QVersionNumber>
 #include <QUrl>
 
 #include <memory>
+#include <optional>
 
 Q_LOGGING_CATEGORY(log, "qtc.designer", QtWarningMsg);
 
@@ -83,6 +89,17 @@ static void reportRenamingError(const QString &oldName, const QString &reason)
                 .arg(oldName, reason));
 }
 
+static std::optional<QVersionNumber> qtVersionFromProject(const Project *project)
+{
+    if (const auto *target = project->activeTarget()) {
+        if (const auto *kit = target->kit(); kit->isValid()) {
+            if (const auto *qtVersion = QtSupport::QtKitAspect::qtVersion(kit))
+                return qtVersion->qtVersion();
+        }
+    }
+    return std::nullopt;
+}
+
 class QtCreatorIntegration::Private
 {
 public:
@@ -142,6 +159,10 @@ QtCreatorIntegration::QtCreatorIntegration(QDesignerFormEditorInterface *core, Q
             }
         }
     });
+
+    auto *fwm = core->formWindowManager();
+    connect(fwm, &QDesignerFormWindowManagerInterface::activeFormWindowChanged,
+            this, &QtCreatorIntegration::slotActiveFormWindowChanged);
 }
 
 QtCreatorIntegration::~QtCreatorIntegration()
@@ -432,6 +453,40 @@ static ClassDocumentPtrPair
     return ClassDocumentPtrPair(0, Document::Ptr());
 }
 
+void QtCreatorIntegration::slotActiveFormWindowChanged(QDesignerFormWindowInterface *formWindow)
+{
+    if (formWindow == nullptr
+        || !setQtVersionFromFile(Utils::FilePath::fromString(formWindow->fileName()))) {
+        resetQtVersion();
+    }
+}
+
+// Set the file's Qt version on the integration for Qt Designer to write
+// it out in the appropriate format (PYSIDE-2492, scoped enum support).
+bool QtCreatorIntegration::setQtVersionFromFile(const Utils::FilePath &filePath)
+{
+    if (const auto *uiProject = ProjectManager::projectForFile(filePath)) {
+        if (auto versionOpt = qtVersionFromProject(uiProject)) {
+            setQtVersion(versionOpt.value());
+            return true;
+        }
+    }
+    return false;
+}
+
+#if QT_VERSION < QT_VERSION_CHECK(6, 9, 0)
+// FIXME: To be replaced by a real property setter on QDesignerIntegration
+void QtCreatorIntegration::setQtVersion(const QVersionNumber &version)
+{
+    setProperty("qtVersion", QVariant::fromValue(version));
+}
+#endif // < 6.9
+
+void QtCreatorIntegration::resetQtVersion()
+{
+    setQtVersion(QLibraryInfo::version());
+}
+
 void QtCreatorIntegration::slotNavigateToSlot(const QString &objectName, const QString &signalSignature,
         const QStringList &parameterNames)
 {
diff --git a/src/plugins/designer/qtcreatorintegration.h b/src/plugins/designer/qtcreatorintegration.h
index 31e3cdcb32c..1f1496e7360 100644
--- a/src/plugins/designer/qtcreatorintegration.h
+++ b/src/plugins/designer/qtcreatorintegration.h
@@ -8,8 +8,11 @@
 
 QT_BEGIN_NAMESPACE
 class QUrl;
+class QVersionNumber;
 QT_END_NAMESPACE
 
+namespace Utils { class FilePath; }
+
 namespace Designer {
 namespace Internal {
 
@@ -27,10 +30,14 @@ public:
 
     void updateSelection() override;
 
+    bool setQtVersionFromFile(const Utils::FilePath &filePath);
+    void resetQtVersion();
+
 signals:
     void creatorHelpRequested(const QUrl &url);
 
 private:
+    void slotActiveFormWindowChanged(QDesignerFormWindowInterface *formWindow);
     void slotNavigateToSlot(const QString &objectName, const QString &signalSignature, const QStringList &parameterNames);
     void slotDesignerHelpRequested(const QString &manual, const QString &document);
     void slotSyncSettingsToDesigner();
@@ -44,6 +51,10 @@ private:
     void handleSymbolRenameStage2(QDesignerFormWindowInterface *formWindow,
                             const QString &newName, const QString &oldName);
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 9, 0)
+    void setQtVersion(const QVersionNumber &version);
+#endif
+
     class Private;
     Private * const d;
 };