1 files changed, 43 insertions, 6 deletions
diff --git a/src/corelib/global/qoperatingsystemversion_darwin.mm b/src/corelib/global/qoperatingsystemversion_darwin.mm
index 6581244821..f8d9fbd027 100644
--- a/src/corelib/global/qoperatingsystemversion_darwin.mm
+++ b/src/corelib/global/qoperatingsystemversion_darwin.mm
@@ -2,19 +2,56 @@
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
 #include "qoperatingsystemversion_p.h"
+
 #import <Foundation/Foundation.h>
 
+#include <QtCore/qfile.h>
+#include <QtCore/qversionnumber.h>
+
+#if !defined(QT_BOOTSTRAPPED)
+#include <QtCore/qprocess.h>
+#endif
+
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 QOperatingSystemVersionBase QOperatingSystemVersionBase::current_impl()
 {
     NSOperatingSystemVersion osv = NSProcessInfo.processInfo.operatingSystemVersion;
-    QOperatingSystemVersionBase v;
-    v.m_os = currentType();
-    v.m_major = osv.majorVersion;
-    v.m_minor = osv.minorVersion;
-    v.m_micro = osv.patchVersion;
-    return v;
+    QVersionNumber versionNumber(osv.majorVersion, osv.minorVersion, osv.patchVersion);
+
+    if (versionNumber.majorVersion() == 10 && versionNumber.minorVersion() >= 16) {
+        // The process is running in system version compatibility mode,
+        // due to the executable being built against a pre-macOS 11 SDK.
+        // This might happen even if we require a more recent SDK for
+        // building Qt applications, as the Qt 'app' might be a plugin
+        // hosted inside a host that used an earlier SDK. But, since we
+        // require a recent SDK for the Qt app itself, the application
+        // should be prepared for versions numbers beyond 10, and we can
+        // resolve the real version number here.
+#if !defined(QT_BOOTSTRAPPED) && QT_CONFIG(process)
+        QProcess sysctl;
+        QProcessEnvironment nonCompatEnvironment;
+        nonCompatEnvironment.insert("SYSTEM_VERSION_COMPAT"_L1, "0"_L1);
+        sysctl.setProcessEnvironment(nonCompatEnvironment);
+        sysctl.start("/usr/sbin/sysctl"_L1, QStringList() << "-b"_L1 << "kern.osproductversion"_L1);
+        if (sysctl.waitForFinished()) {
+            auto versionString = QString::fromLatin1(sysctl.readAll());
+            auto nonCompatSystemVersion = QVersionNumber::fromString(versionString);
+            if (!nonCompatSystemVersion.isNull())
+                versionNumber = nonCompatSystemVersion;
+        }
+#endif
+    }
+
+    QOperatingSystemVersionBase operatingSystemVersion;
+    operatingSystemVersion.m_os = currentType();
+    operatingSystemVersion.m_major = versionNumber.majorVersion();
+    operatingSystemVersion.m_minor = versionNumber.minorVersion();
+    operatingSystemVersion.m_micro = versionNumber.microVersion();
+
+    return operatingSystemVersion;
 }
 
 QT_END_NAMESPACE