diff --git a/src/qt/notificator.h b/src/qt/notificator.h
--- a/src/qt/notificator.h
+++ b/src/qt/notificator.h
@@ -59,7 +59,7 @@
         None, /**< Ignore informational notifications, and show a modal pop-up
                  dialog for Critical notifications. */
         Freedesktop,           /**< Use DBus org.freedesktop.Notifications */
-        QSystemTray,           /**< Use QSystemTray::showMessage */
+        QSystemTray,           /**< Use QSystemTrayIcon::showMessage() */
         UserNotificationCenter /**< Use the 10.8+ User Notification Center (Mac
                                   only) */
     };
@@ -73,11 +73,10 @@
                     const QIcon &icon, int millisTimeout);
 #endif
     void notifySystray(Class cls, const QString &title, const QString &text,
-                       const QIcon &icon, int millisTimeout);
+                       int millisTimeout);
 #ifdef Q_OS_MAC
-    void notifyMacUserNotificationCenter(Class cls, const QString &title,
-                                         const QString &text,
-                                         const QIcon &icon);
+    void notifyMacUserNotificationCenter(const QString &title,
+                                         const QString &text);
 #endif
 };
 
diff --git a/src/qt/notificator.cpp b/src/qt/notificator.cpp
--- a/src/qt/notificator.cpp
+++ b/src/qt/notificator.cpp
@@ -38,7 +38,7 @@
       trayIcon(_trayIcon)
 #ifdef USE_DBUS
       ,
-      interface(0)
+      interface(nullptr)
 #endif
 {
     if (_trayIcon && _trayIcon->supportsMessages()) {
@@ -147,14 +147,15 @@
 void Notificator::notifyDBus(Class cls, const QString &title,
                              const QString &text, const QIcon &icon,
                              int millisTimeout) {
-    Q_UNUSED(cls);
+    // https://developer.gnome.org/notification-spec/
     // Arguments for DBus call:
     QList<QVariant> args;
 
     // Program Name:
     args.append(programName);
 
-    // Unique ID of this notification type:
+    // Replaces ID; A value of 0 means that this notification won't replace any
+    // existing notifications:
     args.append(0U);
 
     // Application Icon, empty string
@@ -207,12 +208,10 @@
 #endif
 
 void Notificator::notifySystray(Class cls, const QString &title,
-                                const QString &text, const QIcon &icon,
-                                int millisTimeout) {
-    Q_UNUSED(icon);
+                                const QString &text, int millisTimeout) {
     QSystemTrayIcon::MessageIcon sicon = QSystemTrayIcon::NoIcon;
-    switch (cls) // Set icon based on class
-    {
+    // Set icon based on class
+    switch (cls) {
         case Information:
             sicon = QSystemTrayIcon::Information;
             break;
@@ -226,17 +225,13 @@
     trayIcon->showMessage(title, text, sicon, millisTimeout);
 }
 
-// Based on Qt's tray icon implementation
 #ifdef Q_OS_MAC
-void Notificator::notifyMacUserNotificationCenter(Class cls,
-                                                  const QString &title,
-                                                  const QString &text,
-                                                  const QIcon &icon) {
+void Notificator::notifyMacUserNotificationCenter(const QString &title,
+                                                  const QString &text) {
     // icon is not supported by the user notification center yet. OSX will use
     // the app icon.
     MacNotificationHandler::instance()->showNotification(title, text);
 }
-
 #endif
 
 void Notificator::notify(Class cls, const QString &title, const QString &text,
@@ -248,11 +243,11 @@
             break;
 #endif
         case QSystemTray:
-            notifySystray(cls, title, text, icon, millisTimeout);
+            notifySystray(cls, title, text, millisTimeout);
             break;
 #ifdef Q_OS_MAC
         case UserNotificationCenter:
-            notifyMacUserNotificationCenter(cls, title, text, icon);
+            notifyMacUserNotificationCenter(title, text);
             break;
 #endif
         default: