diff --git a/rules.cpp b/rules.cpp
index 2db13454db..a75b7775d4 100644
--- a/rules.cpp
+++ b/rules.cpp
@@ -451,10 +451,8 @@ bool Rules::update(AbstractClient* c, int selection)
         screen = c->screen();
     }
     if NOW_REMEMBER(Activity, activity) {
-        // TODO: ivan - multiple activities support
-        const QString & joinedActivities = c->activities().join(QStringLiteral(","));
-        updated = updated || activity != joinedActivities;
-        activity = joinedActivities;
+        updated = updated || activity != c->activities();
+        activity = c->activities();
     }
     if NOW_REMEMBER(MaximizeVert, maximizevert) {
         updated = updated || maximizevert != bool(c->maximizeMode() & MaximizeVertical);
@@ -565,7 +563,7 @@ APPLY_RULE(ignoregeometry, IgnoreGeometry, bool)
 
 APPLY_RULE(desktop, Desktop, int)
 APPLY_RULE(screen, Screen, int)
-APPLY_RULE(activity, Activity, QString)
+APPLY_RULE(activity, Activity, QStringList)
 APPLY_FORCE_RULE(type, Type, NET::WindowType)
 
 bool Rules::applyMaximizeHoriz(MaximizeMode& mode, bool init) const
@@ -779,7 +777,7 @@ CHECK_FORCE_RULE(OpacityInactive, int)
 CHECK_RULE(IgnoreGeometry, bool)
 
 CHECK_RULE(Desktop, int)
-CHECK_RULE(Activity, QString)
+CHECK_RULE(Activity, QStringList)
 CHECK_FORCE_RULE(Type, NET::WindowType)
 CHECK_RULE(MaximizeVert, MaximizeMode)
 CHECK_RULE(MaximizeHoriz, MaximizeMode)
diff --git a/rules.h b/rules.h
index a830a3fdf2..7ffa0789f8 100644
--- a/rules.h
+++ b/rules.h
@@ -53,7 +53,7 @@ public:
     bool checkIgnoreGeometry(bool ignore, bool init = false) const;
     int checkDesktop(int desktop, bool init = false) const;
     int checkScreen(int screen, bool init = false) const;
-    QString checkActivity(QString activity, bool init = false) const;
+    QStringList checkActivity(QStringList activity, bool init = false) const;
     NET::WindowType checkType(NET::WindowType type) const;
     MaximizeMode checkMaximize(MaximizeMode mode, bool init = false) const;
     bool checkMinimize(bool minimized, bool init = false) const;
@@ -147,7 +147,7 @@ public:
     bool applyIgnoreGeometry(bool& ignore, bool init) const;
     bool applyDesktop(int& desktop, bool init) const;
     bool applyScreen(int& desktop, bool init) const;
-    bool applyActivity(QString& activity, bool init) const;
+    bool applyActivity(QStringList& activity, bool init) const;
     bool applyType(NET::WindowType& type) const;
     bool applyMaximizeVert(MaximizeMode& mode, bool init) const;
     bool applyMaximizeHoriz(MaximizeMode& mode, bool init) const;
@@ -221,7 +221,7 @@ private:
     SetRule desktoprule;
     int screen;
     SetRule screenrule;
-    QString activity;
+    QStringList activity;
     SetRule activityrule;
     NET::WindowType type; // type for setting
     ForceRule typerule;
diff --git a/rulesettings.kcfg b/rulesettings.kcfg
index 1eab15d4ec..0cb10da7e1 100644
--- a/rulesettings.kcfg
+++ b/rulesettings.kcfg
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<kcfg xmlns="http://www.kde.org/standards/kcfg/1.0" 
+<kcfg xmlns="http://www.kde.org/standards/kcfg/1.0"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.kde.org/standards/kcfg/1.0
       http://www.kde.org/standards/kcfg/1.0/kcfg.xsd">
   <kcfgfile arg="true">
@@ -169,7 +169,7 @@
       <default code="true">Rules::UnusedSetRule</default>
     </entry>
 
-    <entry name="activity" type="String">
+    <entry name="activity" type="StringList">
       <label>Activity</label>
     </entry>
     <entry name="activityrule" type="Int">
diff --git a/x11client.cpp b/x11client.cpp
index 4ff18d0ba3..40e646d6e3 100644
--- a/x11client.cpp
+++ b/x11client.cpp
@@ -527,10 +527,10 @@ bool X11Client::manage(xcb_window_t w, bool isMapped)
     workspace()->updateOnAllDesktopsOfTransients(this);   // SELI TODO
     //onAllDesktopsChange(); // Decoration doesn't exist here yet
 
-    QString activitiesList;
+    QStringList activitiesList;
     activitiesList = rules()->checkActivity(activitiesList, !isMapped);
     if (!activitiesList.isEmpty())
-        setOnActivities(activitiesList.split(QStringLiteral(",")));
+        setOnActivities(activitiesList);
 
     QRect geom(windowGeometry.rect());
     bool placementDone = false;
@@ -1912,9 +1912,7 @@ void X11Client::setOnActivities(QStringList newActivitiesList)
     if (!Activities::self()) {
         return;
     }
-    QString joinedActivitiesList = newActivitiesList.join(QStringLiteral(","));
-    joinedActivitiesList = rules()->checkActivity(joinedActivitiesList, false);
-    newActivitiesList = joinedActivitiesList.split(u',', Qt::SkipEmptyParts);
+    newActivitiesList = rules()->checkActivity(newActivitiesList);
 
     QStringList allActivities = Activities::self()->all();
 
@@ -1928,7 +1926,7 @@ void X11Client::setOnActivities(QStringList newActivitiesList)
     }
 
     if (// If we got the request to be on all activities explicitly
-        newActivitiesList.isEmpty() || joinedActivitiesList == Activities::nullUuid() ||
+        newActivitiesList.isEmpty() || newActivitiesList.contains(Activities::nullUuid()) ||
         // If we got a list of activities that covers all activities
         (newActivitiesList.count() > 1 && newActivitiesList.count() == allActivities.count())) {
 
@@ -1937,7 +1935,7 @@ void X11Client::setOnActivities(QStringList newActivitiesList)
         m_client.changeProperty(atoms->activities, XCB_ATOM_STRING, 8, nullUuid.length(), nullUuid.constData());
 
     } else {
-        QByteArray joined = joinedActivitiesList.toLatin1();
+        QByteArray joined = newActivitiesList.join(QStringLiteral(",")).toLatin1();
         activityList = newActivitiesList;
         m_client.changeProperty(atoms->activities, XCB_ATOM_STRING, 8, joined.length(), joined.constData());
     }