diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7555e46..9222ce4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,85 +1,85 @@
 project(katomic)
 
-cmake_minimum_required(VERSION 2.8.12 FATAL_ERROR)
+cmake_minimum_required (VERSION 3.5 FATAL_ERROR)
 set(QT_MIN_VERSION "5.7.0")
 set (KF5_MIN_VERSION "5.30.0")
 
 find_package(ECM ${KF5_MIN_VERSION} REQUIRED CONFIG)
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${ECM_MODULE_PATH} ${ECM_KDE_MODULE_DIR})
 
 find_package(Qt5 ${QT_MIN_VERSION} REQUIRED NO_MODULE COMPONENTS Widgets)
 find_package(KF5 ${KF5_MIN_VERSION} REQUIRED COMPONENTS
     CoreAddons
     Config
     Crash
     WidgetsAddons
     I18n
     XmlGui
     NewStuff
     DocTools
     DBusAddons)
 
 find_package(KF5KDEGames 4.9.0 REQUIRED)
 
 include(FeatureSummary)
 include(ECMInstallIcons)
 include(KDEInstallDirs)
 include(KDEFrameworkCompilerSettings NO_POLICY_SCOPE)
 include(KDECMakeSettings)
 include(ECMAddAppIcon)
 
 add_definitions(-DQT_USE_FAST_CONCATENATION -DQT_USE_FAST_OPERATOR_PLUS)
 
 
 add_subdirectory(levels)
 add_subdirectory(doc)
 
 ########### next target ###############
 
 set(katomic_SRCS
    highscores.cpp
    playfield.cpp
    fielditem.cpp
    molecule.cpp
    main.cpp
    toplevel.cpp
    gamewidget.cpp
    levelset.cpp
    levelsetdelegate.cpp
    chooselevelsetdialog.cpp)
 
 kconfig_add_kcfg_files(katomic_SRCS prefs.kcfgc)
 ki18n_wrap_ui(katomic_SRCS levelsetwidget.ui)
 
 file(GLOB ICONS_SRCS "${CMAKE_CURRENT_SOURCE_DIR}/*-apps-katomic.png")
 ecm_add_app_icon(katomic_SRCS ICONS ${ICONS_SRCS})
 add_executable(katomic ${katomic_SRCS})
 
 target_link_libraries(katomic
     KF5::NewStuff
     KF5KDEGames
     KF5::I18n
     KF5::DBusAddons
     KF5::Crash
     KF5::NewStuff)
 
 install(TARGETS katomic  ${KDE_INSTALL_TARGETS_DEFAULT_ARGS})
 
 
 ########### install files ###############
 
 install(PROGRAMS org.kde.katomic.desktop  DESTINATION  ${KDE_INSTALL_APPDIR})
 install(FILES org.kde.katomic.appdata.xml DESTINATION  ${KDE_INSTALL_METAINFODIR})
 install(FILES katomicui.rc  DESTINATION  ${KDE_INSTALL_KXMLGUI5DIR}/katomic)
 # default theme is installed without .desktop file since KgTheme does not need it
 # when only one theme is available. See: 30a1cadd20
 install(FILES default_theme.svgz  DESTINATION  ${KDE_INSTALL_DATADIR}/katomic/pics/)
 install(FILES katomic.knsrc  DESTINATION  ${KDE_INSTALL_CONFDIR})
 
 ecm_install_icons(ICONS 128-apps-katomic.png 16-apps-katomic.png 22-apps-katomic.png 32-apps-katomic.png 48-apps-katomic.png 64-apps-katomic.png DESTINATION ${KDE_INSTALL_ICONDIR} THEME hicolor)
 
 if(NOT WIN32)
   install(PROGRAMS katomic-levelset-upd.pl DESTINATION  ${KDE_INSTALL_KCONFUPDATEDIR})
   install(FILES katomic-levelset.upd DESTINATION  ${KDE_INSTALL_KCONFUPDATEDIR})
 endif(NOT WIN32)
 feature_summary(WHAT ALL INCLUDE_QUIET_PACKAGES FATAL_ON_MISSING_REQUIRED_PACKAGES)