Index: sysutils/lxqt-config/Makefile
===================================================================
--- sysutils/lxqt-config/Makefile
+++ sysutils/lxqt-config/Makefile
@@ -14,7 +14,7 @@
 BUILD_DEPENDS=	${LOCALBASE}/lib/xorg/modules/input/libinput_drv.so:x11-drivers/xf86-input-libinput
 LIB_DEPENDS=	libudev.so:devel/libudev-devd
 
-USES=	cmake compiler:c++14-lang kde:5 localbase:ldflags lxqt qt:5 \
+USES=	cmake compiler:c++17-lang kde:5 localbase:ldflags lxqt qt:5 \
 	pkgconfig tar:xz xorg gnome
 USE_QT=	buildtools:build qmake:build concurrent core dbus \
 	gui linguisttools svg widgets x11extras xml
@@ -24,4 +24,8 @@
 USE_XORG=	ice sm x11 xcb xcursor xext xfixes xrandr xi
 USE_LDCONFIG=	yes
 
+# Override default of c++14 set by lxqt-buildtools
+# This is needed as KScreen introduced code requiring c++17
+CMAKE_ARGS=	-DCMAKE_CXX_STANDARD=17 -DCMAKE_CXX_EXTENSIONS=OFF
+
 .include <bsd.port.mk>
Index: sysutils/lxqt-config/files/patch-kscreen-mode-explicit
===================================================================
--- /dev/null
+++ sysutils/lxqt-config/files/patch-kscreen-mode-explicit
@@ -0,0 +1,80 @@
+From 6add4e4f0040693e7c4242fbae48c9d32007686c Mon Sep 17 00:00:00 2001
+From: Mamoru TASAKA <mtasaka@fedoraproject.org>
+Date: Fri, 3 Feb 2023 08:11:04 +0900
+Subject: [PATCH] lxqt-config-monitor: add more header file inclusion for
+ libkscreen 5.26.90 (#915)
+
+With https://github.com/KDE/libkscreen/commit/94f330959b0eda775418aef7faee80ce69144e63 ,
+`#include <KScreen/Output>` no longer includes "mode.h" implicitly.
+So in lxqt-config-monitor, files using `class KScreen::Mode` should include
+`#include <KScreen/Mode>` explicitly.
+
+Related: #903 .
+---
+ lxqt-config-monitor/kscreenutils.cpp          | 1 +
+ lxqt-config-monitor/loadsettings.cpp          | 1 +
+ lxqt-config-monitor/monitorpicture.cpp        | 1 +
+ lxqt-config-monitor/monitorsettingsdialog.cpp | 1 +
+ lxqt-config-monitor/monitorwidget.cpp         | 1 +
+ 5 files changed, 5 insertions(+)
+
+diff --git lxqt-config-monitor/kscreenutils.cpp.orig lxqt-config-monitor/kscreenutils.cpp
+index 9515e789..be2634d7 100644
+--- lxqt-config-monitor/kscreenutils.cpp.orig
++++ lxqt-config-monitor/kscreenutils.cpp
+@@ -2,6 +2,7 @@
+ #include "timeoutdialog.h"
+ 
+ #include <KScreen/Output>
++#include <KScreen/Mode>
+ #include <KScreen/Config>
+ #include <KScreen/GetConfigOperation>
+ #include <KScreen/SetConfigOperation>
+diff --git lxqt-config-monitor/loadsettings.cpp.orig lxqt-config-monitor/loadsettings.cpp
+index 0c7bd73c..4e9331ba 100644
+--- lxqt-config-monitor/loadsettings.cpp.orig
++++ lxqt-config-monitor/loadsettings.cpp
+@@ -23,6 +23,7 @@
+ #include "kscreenutils.h"
+ #include <KScreen/Output>
+ #include <KScreen/Config>
++#include <KScreen/Mode>
+ #include <KScreen/GetConfigOperation>
+ #include <KScreen/SetConfigOperation>
+ #include <LXQt/Settings>
+diff --git lxqt-config-monitor/monitorpicture.cpp.orig lxqt-config-monitor/monitorpicture.cpp
+index 0d06ab82..4cb14894 100644
+--- lxqt-config-monitor/monitorpicture.cpp.orig
++++ lxqt-config-monitor/monitorpicture.cpp
+@@ -24,6 +24,7 @@
+ #include <QDebug>
+ #include <QVector2D>
+ #include <QRectF>
++#include <KScreen/Mode>
+ #include <QScrollBar>
+ 
+ #include "configure.h"
+diff --git lxqt-config-monitor/monitorsettingsdialog.cpp.orig lxqt-config-monitor/monitorsettingsdialog.cpp
+index 6172019f..bfd8c1dd 100644
+--- lxqt-config-monitor/monitorsettingsdialog.cpp.orig
++++ lxqt-config-monitor/monitorsettingsdialog.cpp
+@@ -28,6 +28,7 @@
+ #include "kscreenutils.h"
+ 
+ #include <KScreen/Output>
++#include <KScreen/Mode>
+ #include <QJsonObject>
+ #include <QJsonArray>
+ #include <LXQt/Settings>
+diff --git lxqt-config-monitor/monitorwidget.cpp.orig lxqt-config-monitor/monitorwidget.cpp
+index e0fcf0a8..41883c25 100644
+--- lxqt-config-monitor/monitorwidget.cpp.orig
++++ lxqt-config-monitor/monitorwidget.cpp
+@@ -22,6 +22,7 @@
+ #include <QComboBox>
+ #include <QStringBuilder>
+ #include <QDialogButtonBox>
++#include <KScreen/Mode>
+ #include <KScreen/EDID>
+ 
+ #include <algorithm>