https://phabricator.kde.org/file/data/dyr2qr4wrhxg4eahkgd3/PHID-FILE-7d4og3zr4mk53u6lzkk2/D27442.diff
https://bugs.kde.org/show_bug.cgi?id=417316

diff -ru kscreen-5.17.5-orig/kcm/package/contents/ui/main.qml kscreen-5.17.5/kcm/package/contents/ui/main.qml
--- kscreen-5.17.5-orig/kcm/package/contents/ui/main.qml	2020-01-07 16:28:39.000000000 +0100
+++ kscreen-5.17.5/kcm/package/contents/ui/main.qml	2020-04-03 17:54:26.097809557 +0200
@@ -24,8 +24,8 @@
 KCM.SimpleKCM {
     id: root
 
-    implicitWidth: units.gridUnit * 30
-    implicitHeight: units.gridUnit * 38
+    implicitWidth: Kirigami.Units.gridUnit * 32
+    implicitHeight: Kirigami.Units.gridUnit * 38
 
     property int selectedOutput: 0
 
@@ -113,7 +113,7 @@
             id: screen
 
             Layout.alignment: Qt.AlignHCenter
-            Layout.preferredWidth: Math.max(root.width * 0.8, units.gridUnit * 26)
+            Layout.preferredWidth: Math.max(root.width * 0.8, Kirigami.Units.gridUnit * 26)
             Layout.topMargin: Kirigami.Units.smallSpacing
             Layout.bottomMargin: Kirigami.Units.largeSpacing * 2
 
diff -ru kscreen-5.17.5-orig/kcm/package/contents/ui/Output.qml kscreen-5.17.5/kcm/package/contents/ui/Output.qml
--- kscreen-5.17.5-orig/kcm/package/contents/ui/Output.qml	2020-01-07 16:28:39.000000000 +0100
+++ kscreen-5.17.5/kcm/package/contents/ui/Output.qml	2020-04-03 17:53:22.491686708 +0200
@@ -19,6 +19,7 @@
 import QtQuick.Layouts 1.1
 import QtQuick.Controls 2.3 as Controls
 import QtGraphicalEffects 1.0
+import org.kde.kirigami 2.4 as Kirigami
 
 Rectangle {
     id: output
@@ -77,7 +78,7 @@
 
             Controls.Label {
                 Layout.fillWidth: true
-                Layout.margins: units.smallSpacing
+                Layout.margins: Kirigami.Units.smallSpacing
 
                 text: model.display
                 wrapMode: Text.Wrap
@@ -87,7 +88,7 @@
 
             Controls.Label {
                 Layout.fillWidth: true
-                Layout.bottomMargin: units.smallSpacing
+                Layout.bottomMargin: Kirigami.Units.smallSpacing
 
                 text: "(" + model.size.width + "x" + model.size.height + ")"
                 horizontalAlignment: Text.AlignHCenter
diff -ru kscreen-5.17.5-orig/kcm/package/contents/ui/Screen.qml kscreen-5.17.5/kcm/package/contents/ui/Screen.qml
--- kscreen-5.17.5-orig/kcm/package/contents/ui/Screen.qml	2020-01-07 16:28:39.000000000 +0100
+++ kscreen-5.17.5/kcm/package/contents/ui/Screen.qml	2020-04-03 17:53:22.491686708 +0200
@@ -45,7 +45,7 @@
     property int xOffset: (width - totalSize.width / relativeFactor) / 2;
     property int yOffset: (height - totalSize.height / relativeFactor) / 2;
 
-    implicitHeight: Math.max(root.height * 0.4, units.gridUnit * 13)
+    implicitHeight: Math.max(root.height * 0.4, Kirigami.Units.gridUnit * 13)
 
     Component.onCompleted: background.visible = true;
 
@@ -54,7 +54,7 @@
         anchors {
             bottom: parent.bottom
             horizontalCenter: parent.horizontalCenter
-            margins: units.smallSpacing
+            margins: Kirigami.Units.smallSpacing
         }
         spacing: units.smallSpacing
         Controls.Button {