diff --git a/Application.cpp b/Application.cpp
index dc03350..a02dfd1 100644
--- a/Application.cpp
+++ b/Application.cpp
@@ -37,6 +37,8 @@
 #include <userenv.h>
 #include <wtsapi32.h>
 
+#include <span>
+
 using namespace Qt::StringLiterals;
 
 int main( int argc, char *argv[] )
@@ -53,8 +55,8 @@ Application::Application( int &argc, char **argv )
 	if( log.exists() && log.open( QFile::WriteOnly|QFile::Append ) )
 		qInstallMessageHandler( msgHandler );
 
-	QTranslator *qt = new QTranslator( this );
-	QTranslator *t = new QTranslator( this );
+	auto *qt = new QTranslator(this);
+	auto *t = new QTranslator(this);
 	QString lang;
 	auto languages = QLocale().uiLanguages().first();
 	if(languages.contains("et"_L1, Qt::CaseInsensitive))
@@ -83,7 +85,7 @@ Application::~Application()
 	qInstallMessageHandler(nullptr);
 }
 
-int Application::confTask( const QStringList &args ) const
+int Application::confTask(const QStringList &args)
 {
 	ScheduledUpdateTask task;
 	if(args.contains("-status"_L1))
@@ -106,29 +108,32 @@ bool Application::execute(const QStringList &arguments)
 	QString command = QDir::toNativeSeparators(applicationFilePath()) + ' ' + arguments.join(' ');
 	qDebug() << "command:" << command;
 
-	PWTS_SESSION_INFOW sessionInfo = 0;
+	PWTS_SESSION_INFOW sessionInfo {};
 	DWORD count = 0;
-	WTSEnumerateSessionsW(WTS_CURRENT_SERVER_HANDLE, 0, 1, &sessionInfo, &count);
+	auto ret = WTSEnumerateSessionsW(WTS_CURRENT_SERVER_HANDLE, 0, 1, &sessionInfo, &count);
+	qDebug() << "WTSEnumerateSessionsW" << ret << GetLastError();
+	if(!ret)
+		return false;
 
 	DWORD sessionId = 0;
-	for(DWORD i = 0; i < count; ++i)
+	for(const auto &session: std::span(sessionInfo, count))
 	{
-		if(sessionInfo[i].State == WTSActive)
+		if(session.State == WTSActive)
 		{
-			sessionId = sessionInfo[i].SessionId;
+			sessionId = session.SessionId;
 			break;
 		}
 	}
 	WTSFreeMemory(sessionInfo);
 	qDebug() << "Active session ID " << sessionId;
 
-	HANDLE currentToken = 0;
-	BOOL ret = WTSQueryUserToken(sessionId, &currentToken);
+	HANDLE currentToken {};
+	ret = WTSQueryUserToken(sessionId, &currentToken);
 	qDebug() << "WTSQueryUserToken" << ret << GetLastError();
 	if(!ret)
 		return false;
 
-	HANDLE primaryToken = 0;
+	HANDLE primaryToken {};
 	ret = DuplicateTokenEx(currentToken, TOKEN_ASSIGN_PRIMARY | TOKEN_ALL_ACCESS, 0,
 		SecurityImpersonation, TokenPrimary, &primaryToken);
 	CloseHandle(currentToken);
@@ -140,7 +145,7 @@ bool Application::execute(const QStringList &arguments)
 	if(!primaryToken)
 		return false;
 
-	void *environment = nullptr;
+	void *environment {};
 	ret = CreateEnvironmentBlock(&environment, primaryToken, true);
 	qDebug() << "CreateEnvironmentBlock" << environment << ret <<  GetLastError();
 
@@ -162,17 +167,17 @@ void Application::messageReceived( const QString &str )
 	w->checkUpdates(str.contains("-autoupdate"_L1), str.contains("-autoclose"_L1));
 }
 
-void Application::msgHandler( QtMsgType type, const QMessageLogContext &, const QString &msg )
+void Application::msgHandler(QtMsgType type, const QMessageLogContext &/* ctx */, const QString &msg)
 {
-	QFile *log = &qobject_cast<Application*>(qApp)->log;
-	log->write(QDateTime::currentDateTime().toString(u"yyyy-MM-dd hh:mm:ss:zzz "_s).toUtf8());
+	QFile &log = qobject_cast<Application*>(qApp)->log;
+	log.write(QDateTime::currentDateTime().toString(u"yyyy-MM-dd hh:mm:ss:zzz "_s).toUtf8());
 	switch( type )
 	{
-	case QtDebugMsg: log->write("DBG: %1\n"_L1.arg(msg).toUtf8()); break;
-	case QtInfoMsg: log->write("INF: %1\n"_L1.arg(msg).toUtf8()); break;
-	case QtWarningMsg: log->write("WRN: %1\n"_L1.arg(msg).toUtf8()); break;
-	case QtCriticalMsg: log->write("CRI: %1\n"_L1.arg( msg).toUtf8()); break;
-	case QtFatalMsg: log->write("FAT: %1\n"_L1.arg(msg).toUtf8()); abort();
+	case QtDebugMsg: log.write("DBG: %1\n"_L1.arg(msg).toUtf8()); break;
+	case QtInfoMsg: log.write("INF: %1\n"_L1.arg(msg).toUtf8()); break;
+	case QtWarningMsg: log.write("WRN: %1\n"_L1.arg(msg).toUtf8()); break;
+	case QtCriticalMsg: log.write("CRI: %1\n"_L1.arg( msg).toUtf8()); break;
+	case QtFatalMsg: log.write("FAT: %1\n"_L1.arg(msg).toUtf8()); abort();
 	}
 }
 
diff --git a/Application.h b/Application.h
index 01d1dd5..516c8c2 100644
--- a/Application.h
+++ b/Application.h
@@ -38,8 +38,8 @@ class Application: public QtSingleApplication
 	bool execute(const QStringList &arguments);
 	void messageReceived( const QString &str );
 	static void msgHandler( QtMsgType type, const QMessageLogContext &ctx, const QString &msg );
-	int confTask( const QStringList &args ) const;
-	void printHelp();
+	static int confTask(const QStringList &args);
+	static void printHelp();
 
 	QFile log;
 	QString url;
diff --git a/README.md b/README.md
index b361dba..2337ec4 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@
 ## Building
 [![Build Status](https://github.com/open-eid/updater/workflows/CI/badge.svg?branch=master)](https://github.com/open-eid/updater/actions)
 
-### OSX
+### Windows
 
 1. Fetch the source
 
@@ -23,6 +23,21 @@
 
         cmake --build build
 
+### OSX
+
+1. Fetch the source
+
+        git clone https://github.com/open-eid/updater
+        cd updater
+
+2. Configure
+
+        cmake -B build -S .
+
+3. Build
+
+        cmake --build build
+
 4. Install
 
         sudo cmake --build build --target install
diff --git a/ScheduledUpdateTask.cpp b/ScheduledUpdateTask.cpp
index d91fb7c..5e10957 100644
--- a/ScheduledUpdateTask.cpp
+++ b/ScheduledUpdateTask.cpp
@@ -34,16 +34,15 @@
 template <class T>
 struct CPtr
 {
-    T *d{};
-    ~CPtr() { if(d) d->Release(); }
-    inline T* operator->() const { return d; }
-    inline operator T*() const { return d; }
-    inline T** operator&() { return &d; }
+	T *d{};
+	~CPtr() { if(d) d->Release(); }
+	constexpr T* operator->() const { return d; }
+	constexpr operator T*() const { return d; }
+	constexpr T** operator&() { return &d; }
 };
 
-class ScheduledUpdateTaskPrivate
+struct ScheduledUpdateTask::Private
 {
-public:
 	CPtr<ITaskService> service;
 	CPtr<ITaskFolder> folder;
 };
@@ -51,7 +50,7 @@ class ScheduledUpdateTaskPrivate
 
 
 ScheduledUpdateTask::ScheduledUpdateTask()
-	: d(new ScheduledUpdateTaskPrivate)
+	: d(std::make_unique<Private>())
 {
 	CoInitialize(nullptr);
 	CoInitializeSecurity(nullptr, -1, nullptr, nullptr, RPC_C_AUTHN_LEVEL_PKT_PRIVACY,
@@ -64,7 +63,7 @@ ScheduledUpdateTask::ScheduledUpdateTask()
 
 ScheduledUpdateTask::~ScheduledUpdateTask()
 {
-	delete d;
+	d.reset();
 	CoUninitialize();
 }
 
@@ -84,6 +83,7 @@ bool ScheduledUpdateTask::configure(ScheduledUpdateTask::Interval interval)
 		settings->put_RunOnlyIfNetworkAvailable(VARIANT_TRUE);
 		settings->put_DisallowStartIfOnBatteries(VARIANT_FALSE);
 		settings->put_StopIfGoingOnBatteries(VARIANT_FALSE);
+		settings->put_MultipleInstances(TASK_INSTANCES_STOP_EXISTING);
 	}
 
 	CPtr<ITriggerCollection> triggerCollection;
@@ -139,7 +139,7 @@ bool ScheduledUpdateTask::configure(ScheduledUpdateTask::Interval interval)
 	}
 	}
 
-	QString command = QDir::toNativeSeparators(qApp->applicationFilePath());
+	QString command = QDir::toNativeSeparators(QCoreApplication::applicationFilePath());
 	CPtr<IActionCollection> actionCollection;
 	CPtr<IAction> action;
 	CPtr<IExecAction> execAction;
diff --git a/ScheduledUpdateTask.h b/ScheduledUpdateTask.h
index cccfd07..1485e6c 100644
--- a/ScheduledUpdateTask.h
+++ b/ScheduledUpdateTask.h
@@ -19,9 +19,8 @@
 
 #pragma once
 
-#include <QString>
+#include <memory>
 
-class ScheduledUpdateTaskPrivate;
 class ScheduledUpdateTask
 {
 public:
@@ -39,5 +38,6 @@ class ScheduledUpdateTask
 	bool remove();
 
 private:
-	ScheduledUpdateTaskPrivate *d;
+	struct Private;
+	std::unique_ptr<Private> d;
 };
diff --git a/common b/common
index 1ab87b3..f748156 160000
--- a/common
+++ b/common
@@ -1 +1 @@
-Subproject commit 1ab87b394ecbd6c7618c96f8c8dda9122fc1cd57
+Subproject commit f74815645e904557a09ae055885a658006811e89
diff --git a/idupdater.cpp b/idupdater.cpp
index abbb74d..a9a34ae 100644
--- a/idupdater.cpp
+++ b/idupdater.cpp
@@ -43,7 +43,6 @@
 using namespace Qt::StringLiterals;
 
 idupdaterui::idupdaterui( const QString &version, idupdater *parent )
-:	QWidget()
 {
 	setupUi( this );
 	m_message->hide();
@@ -152,7 +151,7 @@ void idupdater::finished(bool /*changed*/, const QString &err)
 
 	QJsonObject obj = conf->object();
 	trusted.clear();
-	for(const auto array = conf->object().value("CERT-BUNDLE"_L1).toArray(); const auto &c: array)
+	for(const auto array = conf->rawObject().value("CERT-BUNDLE"_L1).toArray(); const auto &c: array)
 		trusted.append(QSslCertificate(QByteArray::fromBase64(c.toString().toLatin1()), QSsl::Der));
 	if(obj.contains("UPDATER-MESSAGE-URL"_L1))
 	{
@@ -196,7 +195,7 @@ void idupdater::finished(bool /*changed*/, const QString &err)
 	if(w) w->setInfo(version, available);
 }
 
-QString idupdater::installedVersion(const QString &upgradeCode) const
+QString idupdater::installedVersion(const QString &upgradeCode)
 {
 	QString code = upgradeCode.toUpper();
 	QSettings s(u"HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall"_s, QSettings::Registry32Format);
@@ -212,7 +211,7 @@ QString idupdater::installedVersion(const QString &upgradeCode) const
 		return {};
 
 	DWORD size = 0;
-	MsiGetProductInfo(prodCode, INSTALLPROPERTY_VERSIONSTRING, 0, &size);
+	MsiGetProductInfo(prodCode, INSTALLPROPERTY_VERSIONSTRING, nullptr, &size);
 	QString version(size, '\0');
 	size += 1;
 	MsiGetProductInfo(prodCode, INSTALLPROPERTY_VERSIONSTRING, LPWSTR(version.data()), &size);
@@ -299,16 +298,20 @@ bool idupdater::verifyPackage(const QString &filePath) const
 	if(!trusted.contains(cert))
 		return false;
 
-	WINTRUST_FILE_INFO FileData { sizeof(WINTRUST_FILE_INFO) };
-	FileData.pcwszFilePath = LPCWSTR(path.utf16());
+	WINTRUST_FILE_INFO FileData {
+		.cbStruct = sizeof(WINTRUST_FILE_INFO),
+		.pcwszFilePath = LPCWSTR(path.utf16()),
+	};
 
-	WINTRUST_DATA WinTrustData { sizeof(WinTrustData) };
-	WinTrustData.dwUIChoice = m_autoupdate ? WTD_UI_NONE : WTD_UI_ALL;
-	WinTrustData.fdwRevocationChecks = WTD_REVOKE_NONE;
-	WinTrustData.dwUnionChoice = WTD_CHOICE_FILE;
-	WinTrustData.dwProvFlags = WTD_SAFER_FLAG;
-	WinTrustData.pFile = &FileData;
+	WINTRUST_DATA WinTrustData {
+		.cbStruct = sizeof(WinTrustData),
+		.dwUIChoice = DWORD(m_autoupdate ? WTD_UI_NONE : WTD_UI_ALL),
+		.fdwRevocationChecks = WTD_REVOKE_NONE,
+		.dwUnionChoice = WTD_CHOICE_FILE,
+		.pFile = &FileData,
+		.dwProvFlags = WTD_SAFER_FLAG,
+	};
 
 	GUID WVTPolicyGUID = WINTRUST_ACTION_GENERIC_VERIFY_V2;
-	return WinVerifyTrust(0, &WVTPolicyGUID, &WinTrustData) == ERROR_SUCCESS;
+	return WinVerifyTrust(nullptr, &WVTPolicyGUID, &WinTrustData) == ERROR_SUCCESS;
 }
diff --git a/idupdater.h b/idupdater.h
index f1e1097..21288f1 100644
--- a/idupdater.h
+++ b/idupdater.h
@@ -58,7 +58,7 @@ class idupdater : public QNetworkAccessManager
 
 private:
 	void finished(bool changed, const QString &error);
-	QString installedVersion(const QString &upgradeCode) const;
+	static QString installedVersion(const QString &upgradeCode);
 	bool verifyPackage(const QString &filePath) const;
 
 	bool m_autoupdate = false, m_autoclose = false;