So apparently, you also need a series file. Who woulda' thunk.

debian/changelog

@@ -1,29 +1,8 @@
-liblxqt (2.1.0-0ubuntu1) plucky; urgency=medium
+liblxqt (1.4.0-0ubuntu1~ppa3) jammy; urgency=medium
 
-  * New upstream release.
+  * Backport to Jammy.
-    - Bump build dependencies.
-    - Update symbols from amd64 build logs.
-  * Make the package Lintian-clean.
-
- -- Simon Quigley <tsimonq2@ubuntu.com>  Fri, 15 Nov 2024 15:32:03 -0600
-
-liblxqt (2.0.0-0ubuntu2) oracular; urgency=medium
-
-  * Update symbols from build logs.
-
- -- Rik Mills <rikmills@kde.org>  Fri, 23 Aug 2024 21:22:05 +0100
-
-liblxqt (2.0.0-0ubuntu1) oracular; urgency=medium
-
-  * New upstream release.
-  * Bump build dependencies.
-  * Update copyright file.
-  * Bump Standards-Version to 4.7.0, no changes necessary.
-  * Bump soname.
-  * Adjust package names.
-  * Update symbols file.
 
- -- Aaron Rainbolt <arraybolt3@ubuntu.com>  Thu, 15 Aug 2024 16:03:02 -0500
+ -- Simon Quigley <tsimonq2@ubuntu.com>  Fri, 10 Nov 2023 11:07:35 -0600
 
 liblxqt (1.4.0-0ubuntu1) noble; urgency=medium
 

debian/control

@@ -1,6 +1,6 @@
 Source: liblxqt
 Maintainer: Lubuntu Developers <lubuntu-devel@lists.ubuntu.com>
-Original-Maintainer: LXQt Packaging Team <pkg-lxqt-devel@lists.alioth.debian.org>
+XSBC-Original-Maintainer: LXQt Packaging Team <pkg-lxqt-devel@lists.alioth.debian.org>
 Uploaders: Alf Gaida <agaida@siduction.org>,
            ChangZhuo Chen (陳昌倬) <czchen@debian.org>,
            Andrew Lee (李健秋) <ajqlee@debian.org>
@@ -8,24 +8,24 @@ Section: libs
 Priority: optional
 Build-Depends: debhelper-compat (= 13),
                dh-exec,
-               libkf6windowsystem-dev (>= 6.0.0),
+               libkf5windowsystem-dev (>= 5.36.0),
-               libpolkit-qt6-1-dev,
+               libpolkit-qt5-1-dev,
-               libqt6xdg-dev (>= 4.1.0),
+               libqt5svg5-dev,
-               libqt6xdgiconloader-dev (>= 4.1.0),
+               libqt5x11extras5-dev,
+               libqt5xdg-dev (>= 3.12.0),
+               libqt5xdgiconloader-dev (>= 3.12.0),
                libx11-dev,
-               libxkbcommon-dev (>= 0.5.0),
                libxss-dev,
-               lxqt-build-tools (>= 2.1.0),
+               lxqt-build-tools (>= 0.13.0)
-               qt6-svg-dev (>= 6.6.0)
+Standards-Version: 4.6.2
-Standards-Version: 4.7.0
 Vcs-Browser: https://git.lubuntu.me/Lubuntu/liblxqt-packaging
 Vcs-Git: https://git.lubuntu.me/Lubuntu/liblxqt-packaging.git
-Debian-Vcs-Browser: https://salsa.debian.org/lxqt-team/liblxqt
+XS-Debian-Vcs-Browser: https://salsa.debian.org/lxqt-team/liblxqt
-Debian-Vcs-Git: https://salsa.debian.org/lxqt-team/liblxqt.git
+XS-Debian-Vcs-Git: https://salsa.debian.org/lxqt-team/liblxqt.git
 Homepage: https://github.com/lxqt/liblxqt
 Rules-Requires-Root: no
 
-Package: liblxqt2
+Package: liblxqt1
 Architecture: any
 Depends: desktop-file-utils,
          shared-mime-info,
@@ -33,8 +33,8 @@ Depends: desktop-file-utils,
          ${shlibs:Depends}
 Recommends: liblxqt-l10n
 Pre-Depends: ${misc:Pre-Depends}
-Breaks: liblxqt0 (<< 0.99), liblxqt1
+Breaks: liblxqt0 (<< 0.99)
-Replaces: liblxqt0 (<< 0.99), liblxqt1
+Replaces: liblxqt0 (<< 0.99)
 Description: Shared libraries for LXQt desktop environment (libs)
  LXQt is an advanced, easy-to-use, and fast desktop environment based on Qt
  technologies. It has been tailored for users who value simplicity, speed, and
@@ -44,13 +44,13 @@ Description: Shared libraries for LXQt desktop environment (libs)
  This package contains the shared libraries needed by the LXQt desktop
  environment.
 
-Package: liblxqt2-dev
+Package: liblxqt1-dev
 Architecture: any
 Section: libdevel
-Depends: liblxqt2 (= ${binary:Version}),
+Depends: liblxqt1 (= ${binary:Version}),
-         libqt6xdg-dev (>= 4.1.0),
+         libqt5xdg-dev (>= 3.9.1),
-         libqt6xdgiconloader-dev (>= 4.1.0),
+         libqt5xdgiconloader-dev (>= 3.9.1),
-         lxqt-build-tools (>= 2.1.0),
+         lxqt-build-tools (>= 0.11.0),
          ${misc:Depends}
 Description: Shared libraries for LXQt desktop environment (dev)
  LXQt is an advanced, easy-to-use, and fast desktop environment based on Qt
@@ -64,11 +64,6 @@ Package: liblxqt-l10n
 Architecture: all
 Multi-Arch: foreign
 Section: localization
-Depends: qt6-translations-l10n, ${misc:Depends}
+Depends: qttranslations5-l10n, ${misc:Depends}
 Description: Language package for liblxqt
- LXQt is an advanced, easy-to-use, and fast desktop environment based on Qt
+ This package contains the l10n files needed by the liblxqt.
- technologies. It has been tailored for users who value simplicity, speed, and
- an intuitive interface. Unlike most desktop environments, LXQt also works
- fine with less powerful machines.
- .
- This package contains the l10n files needed by liblxqt.

debian/copyright

@@ -3,7 +3,7 @@ Upstream-Name: liblxqt
 Source: https://github.com/lxqt/liblxqt
 
 Files: *
-Copyright: 2012-2024 LXQt team
+Copyright: 2012-2023 LXQt team
            2010-2013 Razor team
 License: LGPL-2.1+
 
@@ -23,10 +23,16 @@ Copyright: 2012-2013 Alec Moskvin <alecm@gmx.com>
            2018 Luis Pereira <luis.artur.pereira@gmail.com>
 License: LGPL-2.1+
 
+Files: lxqtbacklight.cpp
+       lxqtbacklight.h
+       lxqtbacklight/*
+Copyright: 2016-2018 P.L. Lucas
+License: GPL-2+
+
 Files: debian/*
 Copyright: 2014-2019 Alf Gaida <agaida@siduction.org>
            2022-2023 Simon Quigley <tsimonq2@debian.org>
-           2022-2024 Aaron Rainbolt <arraybolt3@gmail.com>
+           2022-2023 Aaron Rainbolt <arraybolt3@gmail.com>
 License: LGPL-2.1+
 
 License: LGPL-2.1+
@@ -42,3 +48,17 @@ License: LGPL-2.1+
  .
  On Debian systems, the complete text of the GNU Lesser General
  Public License version 2.1 can be found in "/usr/share/common-licenses/LGPL-2.1".
+
+License: GPL-2+
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+ .
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ General Public License for more details.
+ .
+ On Debian systems, the complete text of the GNU General Public
+ License version 2 can be found in "/usr/share/common-licenses/GPL-2".

debian/liblxqt1.lintian-overrides

@@ -0,0 +1,2 @@
+# there will be no manpage for lxqt-backlight_backend
+liblxqt1: no-manual-page [usr/bin/lxqt-backlight_backend]

debian/liblxqt1.symbols

@@ -1,6 +1,6 @@
-# SymbolsHelper-Confirmed: 2.1.0 amd64
+# SymbolsHelper-Confirmed: 1.1.0 amd64 armhf
-liblxqt.so.2 liblxqt2 #MINVER#
+liblxqt.so.1 liblxqt1 #MINVER#
-* Build-Depends-Package: liblxqt2-dev
+* Build-Depends-Package: liblxqt1-dev
  _ZN4LXQt10GridLayout10invalidateEv@Base 1.1.0
  _ZN4LXQt10GridLayout10setStretchE6QFlagsINS0_11StretchFlagEE@Base 1.1.0
  _ZN4LXQt10GridLayout11qt_metacallEN11QMetaObject4CallEiPPv@Base 1.1.0
@@ -8,7 +8,6 @@ liblxqt.so.2 liblxqt2 #MINVER#
  _ZN4LXQt10GridLayout11setGeometryERK5QRect@Base 1.1.0
  _ZN4LXQt10GridLayout11setRowCountEi@Base 1.1.0
  _ZN4LXQt10GridLayout12setDirectionENS0_9DirectionE@Base 1.1.0
- _ZN4LXQt10GridLayout13setItemsOrderENS0_10ItemsOrderE@Base 2.1.0
  _ZN4LXQt10GridLayout14setColumnCountEi@Base 1.1.0
  _ZN4LXQt10GridLayout16setCellFixedSizeE5QSize@Base 1.1.0
  _ZN4LXQt10GridLayout16staticMetaObjectE@Base 1.1.0
@@ -29,7 +28,7 @@ liblxqt.so.2 liblxqt2 #MINVER#
  _ZN4LXQt10GridLayoutD1Ev@Base 1.1.0
  _ZN4LXQt10GridLayoutD2Ev@Base 1.1.0
  _ZN4LXQt10PluginInfo4loadERK7QString@Base 1.1.0
- _ZN4LXQt10PluginInfo6searchERK5QListI7QStringERKS2_S7_@Base 2.0.0
+ _ZN4LXQt10PluginInfo6searchERK11QStringListRK7QStringS6_@Base 1.1.0
  _ZN4LXQt10PluginInfo6searchERK7QStringS3_S3_@Base 1.1.0
  _ZN4LXQt10PluginInfoC1Ev@Base 1.1.0
  _ZN4LXQt10PluginInfoC2Ev@Base 1.1.0
@@ -37,7 +36,7 @@ liblxqt.so.2 liblxqt2 #MINVER#
  _ZN4LXQt10Translator16translateLibraryERK7QString@Base 1.1.0
  _ZN4LXQt10Translator20translateApplicationERK7QString@Base 1.1.0
  _ZN4LXQt10Translator22translationSearchPathsEv@Base 1.1.0
- _ZN4LXQt10Translator25setTranslationSearchPathsERK5QListI7QStringE@Base 2.0.0
+ _ZN4LXQt10Translator25setTranslationSearchPathsERK11QStringList@Base 1.1.0
  _ZN4LXQt11Application10unixSignalEi@Base 1.1.0
  _ZN4LXQt11Application11qt_metacallEN11QMetaObject4CallEiPPv@Base 1.1.0
  _ZN4LXQt11Application11qt_metacastEPKc@Base 1.1.0
@@ -70,7 +69,7 @@ liblxqt.so.2 liblxqt2 #MINVER#
  _ZN4LXQt12ConfigDialog4saveEv@Base 1.1.0
  _ZN4LXQt12ConfigDialog5eventEP6QEvent@Base 1.1.0
  _ZN4LXQt12ConfigDialog5resetEv@Base 1.1.0
- _ZN4LXQt12ConfigDialog7addPageEP7QWidgetRK7QStringRK5QListIS3_E@Base 2.0.0
+ _ZN4LXQt12ConfigDialog7addPageEP7QWidgetRK7QStringRK11QStringList@Base 1.1.0
  _ZN4LXQt12ConfigDialog7addPageEP7QWidgetRK7QStringS5_@Base 1.1.0
  _ZN4LXQt12ConfigDialog7clickedEN16QDialogButtonBox14StandardButtonE@Base 1.1.0
  _ZN4LXQt12ConfigDialog8showPageEP7QWidget@Base 1.1.0
@@ -90,7 +89,7 @@ liblxqt.so.2 liblxqt2 #MINVER#
  _ZN4LXQt12HtmlDelegateD2Ev@Base 1.1.0
  _ZN4LXQt12Notification10clearHintsEv@Base 1.1.0
  _ZN4LXQt12Notification10serverInfoEv@Base 1.1.0
- _ZN4LXQt12Notification10setActionsERK5QListI7QStringEi@Base 2.0.0
+ _ZN4LXQt12Notification10setActionsERK11QStringListi@Base 1.1.0
  _ZN4LXQt12Notification10setSummaryERK7QString@Base 1.1.0
  _ZN4LXQt12Notification10setTimeoutEi@Base 1.1.0
  _ZN4LXQt12Notification11qt_metacallEN11QMetaObject4CallEiPPv@Base 1.1.0
@@ -130,9 +129,9 @@ liblxqt.so.2 liblxqt2 #MINVER#
  _ZN4LXQt12PowerManagerD1Ev@Base 1.1.0
  _ZN4LXQt12PowerManagerD2Ev@Base 1.1.0
  _ZN4LXQt13ProgramFinder11programNameERK7QString@Base 1.1.0
- _ZN4LXQt13ProgramFinder12findProgramsERK5QListI7QStringE@Base 2.0.0
+ _ZN4LXQt13ProgramFinder12findProgramsERK11QStringList@Base 1.1.0
  _ZN4LXQt13ProgramFinder13programExistsERK7QString@Base 1.1.0
- _ZN4LXQt13RotatedWidget10enterEventEP11QEnterEvent@Base 2.0.0
+ _ZN4LXQt13RotatedWidget10enterEventEP6QEvent@Base 1.1.0
  _ZN4LXQt13RotatedWidget10leaveEventEP6QEvent@Base 1.1.0
  _ZN4LXQt13RotatedWidget10paintEventEP11QPaintEvent@Base 1.1.0
  _ZN4LXQt13RotatedWidget10wheelEventEP11QWheelEvent@Base 1.1.0
@@ -278,7 +277,6 @@ liblxqt.so.2 liblxqt2 #MINVER#
  _ZN4LXQt9LXQtThemeD1Ev@Base 1.1.0
  _ZN4LXQt9LXQtThemeD2Ev@Base 1.1.0
  _ZN4LXQt9LXQtThemeaSERKS0_@Base 1.1.0
- _ZNK4LXQt10GridLayout10itemsOrderEv@Base 2.1.0
  _ZNK4LXQt10GridLayout10metaObjectEv@Base 1.1.0
  _ZNK4LXQt10GridLayout11columnCountEv@Base 1.1.0
  _ZNK4LXQt10GridLayout15cellMaximumSizeEv@Base 1.1.0
@@ -339,9 +337,7 @@ liblxqt.so.2 liblxqt2 #MINVER#
  _ZNK4LXQt9LXQtTheme4nameEv@Base 1.1.0
  _ZNK4LXQt9LXQtTheme4pathEv@Base 1.1.0
  _ZNK4LXQt9LXQtTheme7isValidEv@Base 1.1.0
- (optional=templinst)_ZNKSt8_Rb_treeI7QStringSt4pairIKS0_8QVariantESt10_Select1stIS4_ESt4lessIS0_ESaIS4_EE4findERS2_@Base 2.0.0
+ _ZNSt6vectorIiSaIiEE17_M_realloc_insertIJiEEEvN9__gnu_cxx17__normal_iteratorIPiS1_EEDpOT_@Base 1.1.0
- (optional=templinst)_ZNSt8_Rb_treeI7QStringSt4pairIKS0_8QVariantESt10_Select1stIS4_ESt4lessIS0_ESaIS4_EE24_M_get_insert_unique_posERS2_@Base 2.0.0
- (optional=templinst|arch=!armhf !s390x)_ZNSt8_Rb_treeI7QStringSt4pairIKS0_8QVariantESt10_Select1stIS4_ESt4lessIS0_ESaIS4_EE29_M_get_insert_hint_unique_posESt23_Rb_tree_const_iteratorIS4_ERS2_@Base 2.0.0
  _ZTIN4LXQt10GridLayoutE@Base 1.1.0
  _ZTIN4LXQt10MessageBoxE@Base 1.1.0
  _ZTIN4LXQt10PluginInfoE@Base 1.1.0
@@ -399,11 +395,9 @@ liblxqt.so.2 liblxqt2 #MINVER#
  _ZTVN4LXQt5PowerE@Base 1.1.0
  _ZTVN4LXQt8SettingsE@Base 1.1.0
  _ZTVN4LXQt9BacklightE@Base 1.1.0
- _Zls6QDebugRK5QListIN4LXQt10PluginInfoEE@Base 2.0.0
+ (c++|arch=!armhf)"non-virtual thunk to LXQt::ConfigDialog::~ConfigDialog()@Base" 1.1.0
- _Zls6QDebugRKN4LXQt10PluginInfoE@Base 2.0.0
- (c++)"non-virtual thunk to LXQt::ConfigDialog::~ConfigDialog()@Base" 2.0.0
  (c++)"non-virtual thunk to LXQt::GridLayout::invalidate()@Base" 1.1.0
- (c++)"non-virtual thunk to LXQt::GridLayout::setGeometry(QRect const&)@Base" 2.0.0
+ (c++|arch=!armhf)"non-virtual thunk to LXQt::GridLayout::setGeometry(QRect const&)@Base" 1.1.0
- (c++)"non-virtual thunk to LXQt::GridLayout::sizeHint() const@Base" 2.0.0
+ (c++|arch=!armhf)"non-virtual thunk to LXQt::GridLayout::sizeHint() const@Base" 1.1.0
- (c++)"non-virtual thunk to LXQt::GridLayout::~GridLayout()@Base" 2.0.0
+ (c++|arch=!armhf)"non-virtual thunk to LXQt::GridLayout::~GridLayout()@Base" 1.1.0
  (c++)"non-virtual thunk to LXQt::PageSelectWidget::~PageSelectWidget()@Base" 1.1.0

debian/liblxqt2.lintian-overrides

@@ -1,5 +0,0 @@
-# there will be no manpage for lxqt-backlight_backend
-liblxqt2: no-manual-page [usr/bin/lxqt-backlight_backend]
-
-# This is fine
-liblxqt2: application-in-library-section libs [usr/bin/lxqt-backlight_backend]

debian/patches/revert-kx11extras-port.patch

@@ -0,0 +1,49 @@
+Description: Revert port away from deprecated KWindowSystem
+Author: Simon Quigley <tsimonq2@ubuntu.com>
+Origin: backport
+Bug: https://github.com/lxqt/liblxqt/issues/334
+Applied-Upstream: fae257647adc8729b597d9cf9617c81b99f9df42, reverted
+Last-Update: 2023-11-10
+
+--- liblxqt-1.4.0.orig/CMakeLists.txt
++++ liblxqt-1.4.0/CMakeLists.txt
+@@ -8,7 +8,7 @@ project(liblxqt)
+ 
+ 
+ set(LXQTBT_MINIMUM_VERSION "0.13.0")
+-set(KF5_MINIMUM_VERSION "5.101.0")
++set(KF5_MINIMUM_VERSION "5.36.0")
+ set(QT_MINIMUM_VERSION "5.15.0")
+ set(QTXDG_MINIMUM_VERSION "3.12.0")
+ 
+--- liblxqt-1.4.0.orig/lxqtsingleapplication.cpp
++++ liblxqt-1.4.0/lxqtsingleapplication.cpp
+@@ -28,7 +28,6 @@
+ #include "lxqtsingleapplication.h"
+ #include "singleapplicationadaptor.h"
+ #include <KWindowSystem/KWindowSystem>
+-#include <KWindowSystem/KX11Extras>
+ #include <QDBusMessage>
+ #include <QWidget>
+ #include <QDebug>
+@@ -96,16 +95,13 @@ void SingleApplication::activateWindow()
+     if (mActivationWindow) {
+         mActivationWindow->show();
+         WId window = mActivationWindow->effectiveWinId();
++
+         KWindowInfo info(window, KWindowSystem::WMDesktop);
+         int windowDesktop = info.desktop();
+ 
+-        if (windowDesktop != KX11Extras::currentDesktop())
+-            KX11Extras::setCurrentDesktop(windowDesktop);
+-
+-        if (QWindow *w = mActivationWindow->windowHandle())
+-            KWindowSystem::activateWindow(w);
+-         else
+-            qDebug() << Q_FUNC_INFO << "Got null windowHandle";
++        if (windowDesktop != KWindowSystem::currentDesktop())
++            KWindowSystem::setCurrentDesktop(windowDesktop);
++        KWindowSystem::activateWindow(window);
+     } else {
+         qDebug() << Q_FUNC_INFO << "activationWindow not set or null";
+     }

debian/patches/series

@@ -0,0 +1 @@
+revert-kx11extras-port.patch