diff --git a/src/app/upgrade.cpp b/src/app/upgrade.cpp
index cdd7d60b5..5cf8dbec8 100644
--- a/src/app/upgrade.cpp
+++ b/src/app/upgrade.cpp
@@ -33,6 +33,7 @@
 
 #include "base/bittorrent/torrentcontentlayout.h"
 #include "base/logger.h"
+#include "base/preferences.h"
 #include "base/profile.h"
 #include "base/settingsstorage.h"
 #include "base/utils/fs.h"
@@ -110,6 +111,120 @@ namespace
             settingsStorage->removeValue(oldKey);
         }
     }
+
+    void upgradeSchedulerDaysSettings()
+    {
+        auto *settingsStorage = SettingsStorage::instance();
+        const auto key = QString::fromLatin1("Preferences/Scheduler/days");
+        const auto value = settingsStorage->loadValue<QString>(key);
+
+        bool ok = false;
+        const auto number = value.toInt(&ok);
+
+        if (ok)
+        {
+            switch (number)
+            {
+            case 0:
+                settingsStorage->storeValue(key, Scheduler::Days::EveryDay);
+                break;
+            case 1:
+                settingsStorage->storeValue(key, Scheduler::Days::Weekday);
+                break;
+            case 2:
+                settingsStorage->storeValue(key, Scheduler::Days::Weekend);
+                break;
+            case 3:
+                settingsStorage->storeValue(key, Scheduler::Days::Monday);
+                break;
+            case 4:
+                settingsStorage->storeValue(key, Scheduler::Days::Tuesday);
+                break;
+            case 5:
+                settingsStorage->storeValue(key, Scheduler::Days::Wednesday);
+                break;
+            case 6:
+                settingsStorage->storeValue(key, Scheduler::Days::Thursday);
+                break;
+            case 7:
+                settingsStorage->storeValue(key, Scheduler::Days::Friday);
+                break;
+            case 8:
+                settingsStorage->storeValue(key, Scheduler::Days::Saturday);
+                break;
+            case 9:
+                settingsStorage->storeValue(key, Scheduler::Days::Sunday);
+                break;
+            default:
+                LogMsg(QObject::tr("Invalid value found in configuration file, reverting it to default. Key: \"%1\". Invalid value: \"%2\".")
+                    .arg(key, QString::number(number)), Log::WARNING);
+                settingsStorage->removeValue(key);
+                break;
+            }
+        }
+    }
+
+    void upgradeDNSServiceSettings()
+    {
+        auto *settingsStorage = SettingsStorage::instance();
+        const auto key = QString::fromLatin1("Preferences/DynDNS/Service");
+        const auto value = settingsStorage->loadValue<QString>(key);
+
+        bool ok = false;
+        const auto number = value.toInt(&ok);
+
+        if (ok)
+        {
+            switch (number)
+            {
+            case -1:
+                settingsStorage->storeValue(key, DNS::Service::None);
+                break;
+            case 0:
+                settingsStorage->storeValue(key, DNS::Service::DynDNS);
+                break;
+            case 1:
+                settingsStorage->storeValue(key, DNS::Service::NoIP);
+                break;
+            default:
+                LogMsg(QObject::tr("Invalid value found in configuration file, reverting it to default. Key: \"%1\". Invalid value: \"%2\".")
+                    .arg(key, QString::number(number)), Log::WARNING);
+                settingsStorage->removeValue(key);
+                break;
+            }
+        }
+    }
+
+    void upgradeTrayIconStyleSettings()
+    {
+        auto *settingsStorage = SettingsStorage::instance();
+        const auto key = QString::fromLatin1("Preferences/Advanced/TrayIconStyle");
+        const auto value = settingsStorage->loadValue<QString>(key);
+
+        bool ok = false;
+        const auto number = value.toInt(&ok);
+
+        if (ok)
+        {
+            switch (number)
+            {
+            case 0:
+                settingsStorage->storeValue(key, TrayIcon::Style::Normal);
+                break;
+            case 1:
+                settingsStorage->storeValue(key, TrayIcon::Style::MonoDark);
+                break;
+            case 2:
+                settingsStorage->storeValue(key, TrayIcon::Style::MonoLight);
+                break;
+            default:
+                LogMsg(QObject::tr("Invalid value found in configuration file, reverting it to default. Key: \"%1\". Invalid value: \"%2\".")
+                    .arg(key, QString::number(number)), Log::WARNING);
+                settingsStorage->removeValue(key);
+                break;
+            }
+        }
+    }
 }
 
 bool upgrade(const bool /*ask*/)
@@ -117,6 +232,9 @@ bool upgrade(const bool /*ask*/)
     exportWebUIHttpsFiles();
     upgradeTorrentContentLayout();
     upgradeListenPortSettings();
+    upgradeSchedulerDaysSettings();
+    upgradeDNSServiceSettings();
+    upgradeTrayIconStyleSettings();
     return true;
 }
 
diff --git a/src/base/bittorrent/bandwidthscheduler.cpp b/src/base/bittorrent/bandwidthscheduler.cpp
index bf0f493bc..d51cb3c74 100644
--- a/src/base/bittorrent/bandwidthscheduler.cpp
+++ b/src/base/bittorrent/bandwidthscheduler.cpp
@@ -61,7 +61,7 @@ bool BandwidthScheduler::isTimeForAlternative() const
     QTime start = pref->getSchedulerStartTime();
     QTime end = pref->getSchedulerEndTime();
     const QTime now = QTime::currentTime();
-    const int schedulerDays = pref->getSchedulerDays();
+    const Scheduler::Days schedulerDays = pref->getSchedulerDays();
     const int day = QDate::currentDate().dayOfWeek();
     bool alternative = false;
 
@@ -75,20 +75,34 @@ bool BandwidthScheduler::isTimeForAlternative() const
     {
         switch (schedulerDays)
         {
-        case EVERY_DAY:
+        case Scheduler::Days::EveryDay:
             alternative = !alternative;
             break;
-        case WEEK_ENDS:
-            if ((day == 6) || (day == 7))
+        case Scheduler::Days::Monday:
+        case Scheduler::Days::Tuesday:
+        case Scheduler::Days::Wednesday:
+        case Scheduler::Days::Thursday:
+        case Scheduler::Days::Friday:
+        case Scheduler::Days::Saturday:
+        case Scheduler::Days::Sunday:
+            {
+                const int offset = static_cast<int>(Scheduler::Days::Monday) - 1;
+                const int dayOfWeek = static_cast<int>(schedulerDays) - offset;
+                if (day == dayOfWeek)
+                    alternative = !alternative;
+            }
+            break;
+        case Scheduler::Days::Weekday:
+            if ((day >= 1) && (day <= 5))
                 alternative = !alternative;
             break;
-        case WEEK_DAYS:
-            if ((day != 6) && (day != 7))
+        case Scheduler::Days::Weekend:
+            if ((day == 6) || (day == 7))
                 alternative = !alternative;
             break;
         default:
-            if (day == (schedulerDays - 2))
-                alternative = !alternative;
+            Q_ASSERT(false);
+            break;
         }
     }
 
diff --git a/src/base/net/dnsupdater.cpp b/src/base/net/dnsupdater.cpp
index 0f213d02a..8b989a0bd 100644
--- a/src/base/net/dnsupdater.cpp
+++ b/src/base/net/dnsupdater.cpp
@@ -41,7 +41,7 @@ using namespace Net;
 DNSUpdater::DNSUpdater(QObject *parent)
     : QObject(parent)
     , m_state(OK)
-    , m_service(DNS::NONE)
+    , m_service(DNS::Service::None)
 {
     updateCredentials();
 
@@ -143,15 +143,16 @@ QString DNSUpdater::getUpdateUrl() const
     // Service specific
     switch (m_service)
     {
-    case DNS::DYNDNS:
+    case DNS::Service::DynDNS:
         url.setHost("members.dyndns.org");
         break;
-    case DNS::NOIP:
+    case DNS::Service::NoIP:
         url.setHost("dynupdate.no-ip.com");
         break;
     default:
         qWarning() << "Unrecognized Dynamic DNS service!";
-        Q_ASSERT(0);
+        Q_ASSERT(false);
+        break;
     }
     url.setPath("/nic/update");
 
@@ -295,16 +296,17 @@ void DNSUpdater::updateCredentials()
     }
 }
 
-QUrl DNSUpdater::getRegistrationUrl(const int service)
+QUrl DNSUpdater::getRegistrationUrl(const DNS::Service service)
 {
     switch (service)
     {
-    case DNS::DYNDNS:
+    case DNS::Service::DynDNS:
         return {"https://account.dyn.com/entrance/"};
-    case DNS::NOIP:
+    case DNS::Service::NoIP:
         return {"https://www.noip.com/remote-access"};
     default:
-        Q_ASSERT(0);
+        Q_ASSERT(false);
+        break;
     }
     return {};
 }
diff --git a/src/base/net/dnsupdater.h b/src/base/net/dnsupdater.h
index 06723d531..3236833f1 100644
--- a/src/base/net/dnsupdater.h
+++ b/src/base/net/dnsupdater.h
@@ -48,7 +48,7 @@ namespace Net
         explicit DNSUpdater(QObject *parent = nullptr);
         ~DNSUpdater();
 
-        static QUrl getRegistrationUrl(int service);
+        static QUrl getRegistrationUrl(DNS::Service service);
 
     public slots:
         void updateCredentials();
diff --git a/src/base/preferences.cpp b/src/base/preferences.cpp
index 7bbf961f4..f46403a32 100644
--- a/src/base/preferences.cpp
+++ b/src/base/preferences.cpp
@@ -493,14 +493,14 @@ void Preferences::setSchedulerEndTime(const QTime &time)
     setValue("Preferences/Scheduler/end_time", time);
 }
 
-SchedulerDays Preferences::getSchedulerDays() const
+Scheduler::Days Preferences::getSchedulerDays() const
 {
-    return static_cast<SchedulerDays>(value("Preferences/Scheduler/days", EVERY_DAY).toInt());
+    return SettingsStorage::instance()->loadValue("Preferences/Scheduler/days", Scheduler::Days::EveryDay);
 }
 
-void Preferences::setSchedulerDays(const SchedulerDays days)
+void Preferences::setSchedulerDays(const Scheduler::Days days)
 {
-    setValue("Preferences/Scheduler/days", static_cast<int>(days));
+    SettingsStorage::instance()->storeValue("Preferences/Scheduler/days", days);
 }
 
 // Search
@@ -816,12 +816,12 @@ void Preferences::setDynDNSEnabled(const bool enabled)
 
 DNS::Service Preferences::getDynDNSService() const
 {
-    return DNS::Service(value("Preferences/DynDNS/Service", DNS::DYNDNS).toInt());
+    return SettingsStorage::instance()->loadValue("Preferences/DynDNS/Service", DNS::Service::DynDNS);
 }
 
-void Preferences::setDynDNSService(const int service)
+void Preferences::setDynDNSService(const DNS::Service service)
 {
-    setValue("Preferences/DynDNS/Service", service);
+    SettingsStorage::instance()->storeValue("Preferences/DynDNS/Service", service);
 }
 
 QString Preferences::getDynDomainName() const
@@ -1211,12 +1211,12 @@ void Preferences::setConfirmRemoveAllTags(const bool enabled)
 #ifndef Q_OS_MACOS
 TrayIcon::Style Preferences::trayIconStyle() const
 {
-    return TrayIcon::Style(value("Preferences/Advanced/TrayIconStyle", TrayIcon::NORMAL).toInt());
+    return SettingsStorage::instance()->loadValue("Preferences/Advanced/TrayIconStyle", TrayIcon::Style::Normal);
 }
 
 void Preferences::setTrayIconStyle(const TrayIcon::Style style)
 {
-    setValue("Preferences/Advanced/TrayIconStyle", style);
+    SettingsStorage::instance()->storeValue("Preferences/Advanced/TrayIconStyle", style);
 }
 #endif
 
diff --git a/src/base/preferences.h b/src/base/preferences.h
index 8769bc5e4..9b998c975 100644
--- a/src/base/preferences.h
+++ b/src/base/preferences.h
@@ -29,6 +29,7 @@
 
 #pragma once
 
+#include <QObject>
 #include <QtContainerFwd>
 #include <QtGlobal>
 #include <QVariant>
@@ -40,38 +41,50 @@ class QNetworkCookie;
 class QSize;
 class QTime;
 
-enum SchedulerDays
+namespace Scheduler
 {
-    EVERY_DAY,
-    WEEK_DAYS,
-    WEEK_ENDS,
-    MON,
-    TUE,
-    WED,
-    THU,
-    FRI,
-    SAT,
-    SUN
-};
+    Q_NAMESPACE
 
-namespace TrayIcon
-{
-    enum Style
+    enum class Days : int
     {
-        NORMAL = 0,
-        MONO_DARK,
-        MONO_LIGHT
+        EveryDay = 0,
+        Weekday = 1,
+        Weekend = 2,
+        Monday = 3,
+        Tuesday = 4,
+        Wednesday = 5,
+        Thursday = 6,
+        Friday = 7,
+        Saturday = 8,
+        Sunday = 9
     };
+    Q_ENUM_NS(Days)
 }
 
 namespace DNS
 {
-    enum Service
+    Q_NAMESPACE
+
+    enum class Service : int
+    {
+        DynDNS = 0,
+        NoIP = 1,
+        None = -1
+    };
+    Q_ENUM_NS(Service)
+}
+
+namespace TrayIcon
+{
+    Q_NAMESPACE
+
+    enum class Style : int
     {
-        DYNDNS,
-        NOIP,
-        NONE = -1
+        Normal = 0,
+        MonoDark = 1,
+        MonoLight = 2
     };
+    Q_ENUM_NS(Style)
 }
 
 class Preferences : public QObject
@@ -161,8 +174,8 @@ public:
     void setSchedulerStartTime(const QTime &time);
     QTime getSchedulerEndTime() const;
     void setSchedulerEndTime(const QTime &time);
-    SchedulerDays getSchedulerDays() const;
-    void setSchedulerDays(SchedulerDays days);
+    Scheduler::Days getSchedulerDays() const;
+    void setSchedulerDays(Scheduler::Days days);
 
     // Search
     bool isSearchEnabled() const;
@@ -236,7 +249,7 @@ public:
     bool isDynDNSEnabled() const;
     void setDynDNSEnabled(bool enabled);
     DNS::Service getDynDNSService() const;
-    void setDynDNSService(int service);
+    void setDynDNSService(DNS::Service service);
     QString getDynDomainName() const;
     void setDynDomainName(const QString &name);
     QString getDynDNSUsername() const;
diff --git a/src/gui/mainwindow.cpp b/src/gui/mainwindow.cpp
index cbfd77797..1db316dde 100644
--- a/src/gui/mainwindow.cpp
+++ b/src/gui/mainwindow.cpp
@@ -2080,11 +2080,11 @@ QIcon MainWindow::getSystrayIcon() const
 #if (defined(Q_OS_UNIX) && !defined(Q_OS_MACOS))
     switch (style)
     {
-    case TrayIcon::NORMAL:
+    case TrayIcon::Style::Normal:
         return QIcon::fromTheme(QLatin1String("qbittorrent-tray"));
-    case TrayIcon::MONO_DARK:
+    case TrayIcon::Style::MonoDark:
         return QIcon::fromTheme(QLatin1String("qbittorrent-tray-dark"));
-    case TrayIcon::MONO_LIGHT:
+    case TrayIcon::Style::MonoLight:
         return QIcon::fromTheme(QLatin1String("qbittorrent-tray-light"));
     default:
         break;
@@ -2092,11 +2092,11 @@ QIcon MainWindow::getSystrayIcon() const
 #else
     switch (style)
     {
-    case TrayIcon::NORMAL:
+    case TrayIcon::Style::Normal:
         return UIThemeManager::instance()->getIcon(QLatin1String("qbittorrent-tray"));
-    case TrayIcon::MONO_DARK:
+    case TrayIcon::Style::MonoDark:
         return UIThemeManager::instance()->getIcon(QLatin1String("qbittorrent-tray-dark"));
-    case TrayIcon::MONO_LIGHT:
+    case TrayIcon::Style::MonoLight:
         return UIThemeManager::instance()->getIcon(QLatin1String("qbittorrent-tray-light"));
     default:
         break;
diff --git a/src/gui/optionsdialog.cpp b/src/gui/optionsdialog.cpp
index ff64a6445..5a6dae4f6 100644
--- a/src/gui/optionsdialog.cpp
+++ b/src/gui/optionsdialog.cpp
@@ -783,7 +783,7 @@ void OptionsDialog::saveOptions()
     session->setIgnoreLimitsOnLAN(!m_ui->checkLimitLocalPeerRate->isChecked());
     pref->setSchedulerStartTime(m_ui->timeEditScheduleFrom->time());
     pref->setSchedulerEndTime(m_ui->timeEditScheduleTo->time());
-    pref->setSchedulerDays(static_cast<SchedulerDays>(m_ui->comboBoxScheduleDays->currentIndex()));
+    pref->setSchedulerDays(static_cast<Scheduler::Days>(m_ui->comboBoxScheduleDays->currentIndex()));
     session->setBandwidthSchedulerEnabled(m_ui->groupBoxSchedule->isChecked());
 
     auto proxyConfigManager = Net::ProxyConfigurationManager::instance();
@@ -867,7 +867,7 @@ void OptionsDialog::saveOptions()
         pref->setWebUIHostHeaderValidationEnabled(m_ui->groupHostHeaderValidation->isChecked());
         // DynDNS
         pref->setDynDNSEnabled(m_ui->checkDynDNS->isChecked());
-        pref->setDynDNSService(m_ui->comboDNSService->currentIndex());
+        pref->setDynDNSService(static_cast<DNS::Service>(m_ui->comboDNSService->currentIndex()));
         pref->setDynDomainName(m_ui->domainNameTxt->text());
         pref->setDynDNSUsername(m_ui->DNSUsernameTxt->text());
         pref->setDynDNSPassword(m_ui->DNSPasswordTxt->text());
@@ -941,7 +941,7 @@ void OptionsDialog::loadOptions()
     {
         m_ui->checkMinimizeToSysTray->setChecked(pref->minimizeToTray());
         m_ui->checkCloseToSystray->setChecked(pref->closeToTray());
-        m_ui->comboTrayIcon->setCurrentIndex(pref->trayIconStyle());
+        m_ui->comboTrayIcon->setCurrentIndex(static_cast<int>(pref->trayIconStyle()));
     }
 #endif
 
@@ -1832,7 +1832,8 @@ void OptionsDialog::showConnectionTab()
 
 void OptionsDialog::on_registerDNSBtn_clicked()
 {
-    QDesktopServices::openUrl(Net::DNSUpdater::getRegistrationUrl(m_ui->comboDNSService->currentIndex()));
+    const auto service = static_cast<DNS::Service>(m_ui->comboDNSService->currentIndex());
+    QDesktopServices::openUrl(Net::DNSUpdater::getRegistrationUrl(service));
 }
 
 void OptionsDialog::on_IpFilterRefreshBtn_clicked()
diff --git a/src/webui/api/appcontroller.cpp b/src/webui/api/appcontroller.cpp
index a6be72dd5..36cbd80a9 100644
--- a/src/webui/api/appcontroller.cpp
+++ b/src/webui/api/appcontroller.cpp
@@ -198,7 +198,7 @@ void AppController::preferencesAction()
     const QTime end_time = pref->getSchedulerEndTime();
     data["schedule_to_hour"] = end_time.hour();
     data["schedule_to_min"] = end_time.minute();
-    data["scheduler_days"] = pref->getSchedulerDays();
+    data["scheduler_days"] = static_cast<int>(pref->getSchedulerDays());
 
     // Bittorrent
     // Privacy
@@ -264,7 +264,7 @@ void AppController::preferencesAction()
     data["web_ui_reverse_proxies_list"] = pref->getWebUITrustedReverseProxiesList();
     // Update my dynamic domain name
     data["dyndns_enabled"] = pref->isDynDNSEnabled();
-    data["dyndns_service"] = pref->getDynDNSService();
+    data["dyndns_service"] = static_cast<int>(pref->getDynDNSService());
     data["dyndns_username"] = pref->getDynDNSUsername();
     data["dyndns_password"] = pref->getDynDNSPassword();
     data["dyndns_domain"] = pref->getDynDomainName();
@@ -560,7 +560,7 @@ void AppController::setPreferencesAction()
     if (m.contains("schedule_to_hour") && m.contains("schedule_to_min"))
         pref->setSchedulerEndTime(QTime(m["schedule_to_hour"].toInt(), m["schedule_to_min"].toInt()));
     if (hasKey("scheduler_days"))
-        pref->setSchedulerDays(SchedulerDays(it.value().toInt()));
+        pref->setSchedulerDays(static_cast<Scheduler::Days>(it.value().toInt()));
 
     // Bittorrent
     // Privacy
@@ -698,7 +698,7 @@ void AppController::setPreferencesAction()
     if (hasKey("dyndns_enabled"))
         pref->setDynDNSEnabled(it.value().toBool());
     if (hasKey("dyndns_service"))
-        pref->setDynDNSService(it.value().toInt());
+        pref->setDynDNSService(static_cast<DNS::Service>(it.value().toInt()));
     if (hasKey("dyndns_username"))
         pref->setDynDNSUsername(it.value().toString());
     if (hasKey("dyndns_password"))
diff --git a/src/webui/api/synccontroller.cpp b/src/webui/api/synccontroller.cpp
index 7f7798abe..2aac15741 100644
--- a/src/webui/api/synccontroller.cpp
+++ b/src/webui/api/synccontroller.cpp
@@ -282,7 +282,8 @@ namespace
                     }
                     break;
                 default:
-                    Q_ASSERT(0);
+                    Q_ASSERT(false);
+                    break;
                 }
             }