diff --git a/app-text/uchmviewer/files/uchmviewer-8.4-cmake-minreqver-3.16.patch b/app-text/uchmviewer/files/uchmviewer-8.4-cmake-minreqver-3.16.patch
new file mode 100644
index 000000000000..338dc25728d0
--- /dev/null
+++ b/app-text/uchmviewer/files/uchmviewer-8.4-cmake-minreqver-3.16.patch
@@ -0,0 +1,297 @@
+Source: https://github.com/eBookProjects/uChmViewer/pull/58
+
+From d3fecffbc959df7b8b7fa029c3575376c8f9e263 Mon Sep 17 00:00:00 2001
+From: Andreas Sturmlechner <asturm@gentoo.org>
+Date: Thu, 23 Oct 2025 11:34:07 +0200
+Subject: [PATCH 1/2] Raise CMake minimum version to 3.16
+
+CMake 3.31 warns about compat. for <3.10 being removed in the future. Qt6
+CMake modules already require 3.16 though, so it is a good base line.
+
+CMake 3.16 was released in 2019.
+
+Signed-off-by: Andreas Sturmlechner <asturm@gentoo.org>
+---
+ CMakeLists.txt              | 2 +-
+ cmake/Findlibzip.cmake      | 2 +-
+ cmake/get-version.cmake     | 3 +--
+ cmake/qt-aliases.cmake      | 2 +-
+ cmake/use-in.cmake          | 2 +-
+ lib/CMakeLists.txt          | 2 +-
+ lib/libebook/CMakeLists.txt | 2 +-
+ packages/CMakeLists.txt     | 2 +-
+ po/CMakeLists.txt           | 2 +-
+ src/CMakeLists.txt          | 2 +-
+ 10 files changed, 10 insertions(+), 11 deletions(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index dbc9f89..ca4e68f 100755
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -19,7 +19,7 @@
+ #                      The default is ON.
+ ################################################
+ 
+-cmake_minimum_required(VERSION 3.13)
++cmake_minimum_required(VERSION 3.16)
+ 
+ # Project info
+ project(uchmviewer HOMEPAGE_URL "https://github.com/u-235/uchmviewer")
+diff --git a/cmake/Findlibzip.cmake b/cmake/Findlibzip.cmake
+index 580e77a..cba1ed3 100644
+--- a/cmake/Findlibzip.cmake
++++ b/cmake/Findlibzip.cmake
+@@ -1,6 +1,6 @@
+ # Tries to find libzip
+ 
+-cmake_minimum_required(VERSION 3.5)
++cmake_minimum_required(VERSION 3.16)
+ 
+ find_path(libzip_INCLUDE_DIR NAMES zip.h
+     PATHS ${libzip_ROOT}
+diff --git a/cmake/get-version.cmake b/cmake/get-version.cmake
+index ba9e40e..675ce89 100644
+--- a/cmake/get-version.cmake
++++ b/cmake/get-version.cmake
+@@ -1,8 +1,7 @@
+ # Getting the application version from the version.h file.
+ # The result is saved in the APP_VERSION cache variables.
+-# CMAKE_MATCH_n request CMake 3.9
+ 
+-cmake_minimum_required(VERSION 3.9)
++cmake_minimum_required(VERSION 3.16)
+ 
+ set (f_ver "src/version.h")
+ 
+diff --git a/cmake/qt-aliases.cmake b/cmake/qt-aliases.cmake
+index 0e4e0c1..1e7aae1 100644
+--- a/cmake/qt-aliases.cmake
++++ b/cmake/qt-aliases.cmake
+@@ -31,7 +31,7 @@
+ #
+ ################################################################################
+ 
+-cmake_minimum_required(VERSION 3.13)
++cmake_minimum_required(VERSION 3.16)
+ 
+ ############################
+ #  Core macros             #
+diff --git a/cmake/use-in.cmake b/cmake/use-in.cmake
+index 3691e99..1341bc2 100644
+--- a/cmake/use-in.cmake
++++ b/cmake/use-in.cmake
+@@ -3,7 +3,7 @@
+ # Copyright (c) 2022 Nick Egorrov
+ ########################################
+ 
+-cmake_minimum_required(VERSION 3.5)
++cmake_minimum_required(VERSION 3.16)
+ 
+ #[==============================[
+ Attempts to set the cache variable to ON when building for a specific OS.
+diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
+index ce560d0..7cbc530 100644
+--- a/lib/CMakeLists.txt
++++ b/lib/CMakeLists.txt
+@@ -1,5 +1,5 @@
+ 
+-cmake_minimum_required(VERSION 3.5)
++cmake_minimum_required(VERSION 3.16)
+ 
+ if (${USE_STATIC_CHMLIB})
+     set(CHMLIB_SRC_DIR ${CMAKE_CURRENT_LIST_DIR}/CHMLib/src)
+diff --git a/lib/libebook/CMakeLists.txt b/lib/libebook/CMakeLists.txt
+index bdc132e..3b7a48b 100644
+--- a/lib/libebook/CMakeLists.txt
++++ b/lib/libebook/CMakeLists.txt
+@@ -1,5 +1,5 @@
+ 
+-cmake_minimum_required(VERSION 3.5)
++cmake_minimum_required(VERSION 3.16)
+ 
+ # Project files
+ set(CPP_SOURCES
+diff --git a/packages/CMakeLists.txt b/packages/CMakeLists.txt
+index 53e71bd..5e9d5de 100644
+--- a/packages/CMakeLists.txt
++++ b/packages/CMakeLists.txt
+@@ -1,5 +1,5 @@
+ 
+-cmake_minimum_required(VERSION 3.5)
++cmake_minimum_required(VERSION 3.16)
+ 
+ if (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+     install(FILES freedesktop/uchmviewer.desktop DESTINATION ${APP_DEF_INSTALL_DIR})
+diff --git a/po/CMakeLists.txt b/po/CMakeLists.txt
+index 32f4b4a..7af790c 100644
+--- a/po/CMakeLists.txt
++++ b/po/CMakeLists.txt
+@@ -1,6 +1,6 @@
+ # Create and install translation files.
+ 
+-cmake_minimum_required(VERSION 3.5)
++cmake_minimum_required(VERSION 3.16)
+ 
+ set(CATALOG_NAME uchmviewer)
+ # The languages.txt file contains a list of locales.
+diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
+index 9e1c7e5..49c7bfc 100644
+--- a/src/CMakeLists.txt
++++ b/src/CMakeLists.txt
+@@ -1,5 +1,5 @@
+ 
+-cmake_minimum_required(VERSION 3.5)
++cmake_minimum_required(VERSION 3.16)
+ # Need to include generated files.
+ set(CMAKE_INCLUDE_CURRENT_DIR ON)
+ 
+-- 
+2.51.1
+
+
+From 97fab8d74068936adeaf79bc31839e8a2c0666e7 Mon Sep 17 00:00:00 2001
+From: Andreas Sturmlechner <asturm@gentoo.org>
+Date: Thu, 23 Oct 2025 11:56:57 +0200
+Subject: [PATCH 2/2] Do not expand variables beforehand
+
+See also:
+https://invent.kde.org/plasma/libplasma/-/merge_requests/267
+https://cmake.org/cmake/help/latest/command/if.html#variable-expansion
+https://cmake.org/cmake/help/latest/policy/CMP0054.html#policy:CMP0054
+
+Signed-off-by: Andreas Sturmlechner <asturm@gentoo.org>
+---
+ CMakeLists.txt          | 10 +++++-----
+ lib/CMakeLists.txt      |  4 ++--
+ packages/CMakeLists.txt |  4 ++--
+ po/CMakeLists.txt       |  2 +-
+ src/CMakeLists.txt      |  6 +++---
+ 5 files changed, 13 insertions(+), 13 deletions(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index ca4e68f..b6bc021 100755
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -49,7 +49,7 @@ find_package(libzip REQUIRED)
+ set(APP_QT_MIN_VERSION 5.0)
+ set(APP_QT_MODULES Core Network PrintSupport Widgets Xml)
+ # Modules for WebKit or WebEngine.
+-if (${USE_WEBENGINE})
++if (USE_WEBENGINE)
+     set(APP_QT_MIN_VERSION 5.9)
+     list(APPEND APP_QT_MODULES WebEngineWidgets)
+     target_link_libraries(extra INTERFACE Qt::WebEngineWidgets)
+@@ -73,25 +73,25 @@ endif ()
+ 
+ set(QT Qt${QT_VERSION_MAJOR})
+ # Since Qt 6 QTextCodec moved in the Qt 5 Core Compat module.
+-if (${QT_VERSION_MAJOR} GREATER_EQUAL 6)
++if (QT_VERSION_MAJOR GREATER_EQUAL 6)
+     list(APPEND APP_QT_MODULES Core5Compat)
+     target_link_libraries(extra INTERFACE ${QT}::Core5Compat)
+ endif ()
+ 
+-if (${USE_DBUS})
++if (USE_DBUS)
+     list(APPEND APP_QT_MODULES DBus)
+     target_link_libraries(extra INTERFACE Qt::DBus)
+     target_compile_definitions(extra INTERFACE USE_DBUS)
+ endif ()
+ 
+-if (${USE_MAC_APP})
++if (USE_MAC_APP)
+     target_compile_definitions(extra INTERFACE USE_MAC_APP)
+ endif ()
+ 
+ # Now we know all the required Qt modules.
+ find_package(${QT} REQUIRED ${APP_QT_MODULES})
+ 
+-if (${USE_KF5})
++if (USE_KF5)
+     # Needed by find_package(KF5) below.
+     find_package(ECM REQUIRED)
+     list(APPEND CMAKE_MODULE_PATH ${ECM_MODULE_PATH})
+diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
+index 7cbc530..5a12a5d 100644
+--- a/lib/CMakeLists.txt
++++ b/lib/CMakeLists.txt
+@@ -1,10 +1,10 @@
+ 
+ cmake_minimum_required(VERSION 3.16)
+ 
+-if (${USE_STATIC_CHMLIB})
++if (USE_STATIC_CHMLIB)
+     set(CHMLIB_SRC_DIR ${CMAKE_CURRENT_LIST_DIR}/CHMLib/src)
+ 
+-    if (EXISTS ${CHMLIB_SRC_DIR}/chm_lib.h)
++    if (EXISTS CHMLIB_SRC_DIR/chm_lib.h)
+         add_library(chmlib STATIC
+             ${CHMLIB_SRC_DIR}/chm_lib.c
+             ${CHMLIB_SRC_DIR}/chm_lib.h
+diff --git a/packages/CMakeLists.txt b/packages/CMakeLists.txt
+index 5e9d5de..46a5aea 100644
+--- a/packages/CMakeLists.txt
++++ b/packages/CMakeLists.txt
+@@ -1,7 +1,7 @@
+ 
+ cmake_minimum_required(VERSION 3.16)
+ 
+-if (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
++if (CMAKE_SYSTEM_NAME MATCHES "Linux")
+     install(FILES freedesktop/uchmviewer.desktop DESTINATION ${APP_DEF_INSTALL_DIR})
+     install(DIRECTORY freedesktop/icons/ DESTINATION ${APP_ICONS_INSTALL_DIR})
+ elseif (${CMAKE_SYSTEM_NAME} MATCHES "Darwin" AND USE_MACOS_BUNDLE)
+@@ -26,7 +26,7 @@ if (USE_DEPLOY_RUNTIME)
+         install(FILES $<TARGET_FILE:chm> DESTINATION ${APP_BIN_INSTALL_DIR})
+     endif ()
+ 
+-    if (${CMAKE_SYSTEM_NAME} MATCHES "Windows")
++    if (CMAKE_SYSTEM_NAME MATCHES "Windows")
+         # Copying runtime dependencies for Windows deployment
+         # See https://doc.qt.io/qt-5/windows-deployment.html
+         set(QT_DEPLOY_DIR ${CMAKE_CURRENT_BINARY_DIR}/qt-deploy)
+diff --git a/po/CMakeLists.txt b/po/CMakeLists.txt
+index 7af790c..57e6b82 100644
+--- a/po/CMakeLists.txt
++++ b/po/CMakeLists.txt
+@@ -38,7 +38,7 @@ endif ()
+ if (USE_GETTEXT)
+     foreach (LANG ${LANGUAGES})
+         set(CATALOG ${CMAKE_CURRENT_SOURCE_DIR}/${CATALOG_NAME}_${LANG}.po)
+-        if(EXISTS ${CATALOG})
++        if(EXISTS "${CATALOG}")
+             file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/${LANG}/LC_MESSAGES)
+             set(GMO_FILE ${CMAKE_CURRENT_BINARY_DIR}/${LANG}/LC_MESSAGES/${CATALOG_NAME}.mo)
+             list(APPEND GMO_LIST ${GMO_FILE})
+diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
+index 49c7bfc..f0128b4 100644
+--- a/src/CMakeLists.txt
++++ b/src/CMakeLists.txt
+@@ -76,7 +76,7 @@ set(UIS
+     window_browser.ui
+     )
+ 
+-if (${USE_WEBENGINE})
++if (USE_WEBENGINE)
+     list(APPEND CPP_SOURCES
+         qtwebengine/viewwindow.cpp
+         qtwebengine/viewwindow.h
+@@ -94,13 +94,13 @@ else ()
+     list(APPEND MOC_HEADERS qtwebkit/viewwindow.h)
+ endif ()
+ 
+-if (${USE_DBUS})
++if (USE_DBUS)
+     list(APPEND CPP_SOURCES dbus_interface.cpp dbus_interface.h)
+     list(APPEND MOC_HEADERS dbus_interface.h)
+ endif ()
+ 
+ # Mac OS specific
+-if (${USE_MAC_APP})
++if (USE_MAC_APP)
+     list(APPEND CPP_SOURCES uchmviewerapp.cpp uchmviewerapp.h)
+     list(APPEND MOC_HEADERS uchmviewerapp.h)
+ endif ()
+-- 
+2.51.1
+
diff --git a/app-text/uchmviewer/uchmviewer-8.4.ebuild b/app-text/uchmviewer/uchmviewer-8.4.ebuild
index c991da3833ea..45cf71807be0 100644
--- a/app-text/uchmviewer/uchmviewer-8.4.ebuild
+++ b/app-text/uchmviewer/uchmviewer-8.4.ebuild
@@ -25,6 +25,10 @@ DEPEND="
 "
 RDEPEND="${DEPEND}"
 
+PATCHES=(
+	"${FILESDIR}/${P}-cmake-minreqver-3.16.patch" # bug #964965, pending PR
+)
+
 DOCS=( AUTHORS.md ChangeLog DBUS-bindings README.md )
 
 src_configure() {