diff --git a/kconf_update/CMakeLists.txt b/kconf_update/CMakeLists.txt
--- a/kconf_update/CMakeLists.txt
+++ b/kconf_update/CMakeLists.txt
@@ -1,2 +1,4 @@
 install(FILES kwin.upd
         DESTINATION ${KDE_INSTALL_KCONFUPDATEDIR})
+install(PROGRAMS kwin-5.16-auto-bordersize.sh
+        DESTINATION ${KDE_INSTALL_KCONFUPDATEDIR})
diff --git a/kconf_update/kwin-5.16-auto-bordersize.sh b/kconf_update/kwin-5.16-auto-bordersize.sh
new file mode 100644
--- /dev/null
+++ b/kconf_update/kwin-5.16-auto-bordersize.sh
@@ -0,0 +1,24 @@
+#!/bin/sh
+
+HAS_SIZE=''
+HAS_AUTO=''
+
+while read -r line
+do
+  # substring from beginning to equal sign
+  ENTRY="${line%%=*}"
+  if [ "$ENTRY" = "BorderSize" ]; then
+    HAS_SIZE=1
+  fi
+  if [ "$ENTRY" = "BorderSizeAuto" ]; then
+    HAS_AUTO=1
+  fi
+  echo "$line"
+done
+
+if [ -n "$HAS_SIZE" -a -z "$HAS_AUTO" ]; then
+  # unset auto borders if user has set a border
+  # size in the past (for good measure make
+  # also sure auto borders are not yet set)
+  echo "BorderSizeAuto=false"
+fi
diff --git a/kconf_update/kwin.upd b/kconf_update/kwin.upd
--- a/kconf_update/kwin.upd
+++ b/kconf_update/kwin.upd
@@ -25,3 +25,9 @@
 File=kwinrc
 Group=Plugins
 Key=dimscreenEnabled,kwin4_effect_dimscreenEnabled
+
+# Deactivate auto border size if the user has changed border size in the past
+Id=auto-bordersize
+File=kwinrc
+Group=org.kde.kdecoration2
+Script=kwin-5.16-auto-bordersize.sh,sh