Merge #13458: gui: Drop qt4 support

af6ac3b677454644364fd24d0df0c02ac9b8c8db doc: Remove mention of Qt4 from build docs (Wladimir J. van der Laan)
462c71f71b5d753bc8327ab833dea23679450ca3 test: Update travis to not test Qt4 anymore (Wladimir J. van der Laan)
907f73bbc5b6c98b01d7c6088a294dea66634a3f gui: Remove QT_VERSION fallbacks for Qt < 5 (Wladimir J. van der Laan)
bad068ad9f4bc60bfc10e27d4ffaec92d7df8491 build: Build system changes to support only Qt5 (Wladimir J. van der Laan)

Pull request description:

  Implements #8263.

  Qt4.x has been EOL since 2015, and at least Gentoo has, or is going to drop support for it. I wouldn't be surprised if other Linux distributions follow.

  This removes Qt4 detection from the build system, as well as removes all Qt4 fallbacks from the code. Turns out there's more than I expected: this is going to make maintenance of the GUI code, as well as adding new features significantly easier.

  (I know there's still some references left to qt4 in RPM and Debian build script, but I don't have the knowledge how to fix them)

Tree-SHA512: d495924fd4dda6f6566ba44ee96be7cbe62e69ba1ca993b80a8449f78da852b7f1bd3e8200d57cfa1d72233c340eeff4596fb0032ecbddc715d99aea63817d3f
(cherry picked from commit dc53f7f2514026db8a28632371e73e6dbf858083)

# Conflicts:
#	.travis.yml
#	build-aux/m4/bitcoin_qt.m4
#	configure.ac
#	doc/build-osx.md
#	doc/build-unix.md
#	doc/dependencies.md
#	src/qt/README.md
#	src/qt/bitcoingui.cpp
#	src/qt/coincontroldialog.cpp
#	src/qt/dash.cpp
#	src/qt/guiutil.cpp
#	src/qt/macdockiconhandler.mm
#	src/qt/networkstyle.cpp
#	src/qt/openuridialog.cpp
#	src/qt/peertablemodel.cpp
#	src/qt/signverifymessagedialog.cpp
#	src/qt/test/wallettests.cpp
#	src/qt/transactionview.cpp

build-aux/m4/bitcoin_qt.m4

@@ -53,8 +53,8 @@ dnl CAUTION: Do not use this inside of a conditional.
 AC_DEFUN([BITCOIN_QT_INIT],[
   dnl enable qt support
   AC_ARG_WITH([gui],
-    [AS_HELP_STRING([--with-gui@<:@=no|qt4|qt5|auto@:>@],
+    [AS_HELP_STRING([--with-gui@<:@=no|qt5|auto@:>@],
-    [build dash-qt GUI (default=auto, qt5 tried first)])],
+    [build dash-qt GUI (default=auto)])],
     [
      bitcoin_qt_want_version=$withval
      if test "x$bitcoin_qt_want_version" = xyes; then
@@ -94,18 +94,17 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
   fi
 
   if test "x$use_pkgconfig" = xyes; then
-    BITCOIN_QT_CHECK([_BITCOIN_QT_FIND_LIBS_WITH_PKGCONFIG([$2])])
+    BITCOIN_QT_CHECK([_BITCOIN_QT_FIND_LIBS_WITH_PKGCONFIG])
   else
     BITCOIN_QT_CHECK([_BITCOIN_QT_FIND_LIBS_WITHOUT_PKGCONFIG])
   fi
 
   dnl This is ugly and complicated. Yuck. Works as follows:
-  dnl We can't discern whether Qt4 builds are static or not. For Qt5, we can
+  dnl For Qt5, we can check a header to find out whether Qt is build
-  dnl check a header to find out. When Qt is built statically, some plugins must
+  dnl statically. When Qt is built statically, some plugins must be linked into
-  dnl be linked into the final binary as well. These plugins have changed between
+  dnl the final binary as well.
-  dnl Qt4 and Qt5. With Qt5, languages moved into core and the WindowsIntegration
+  dnl With Qt5, languages moved into core and the WindowsIntegration plugin was
-  dnl plugin was added. Since we can't tell if Qt4 is static or not, it is
+  dnl added.
-  dnl assumed for windows builds.
   dnl _BITCOIN_QT_CHECK_STATIC_PLUGINS does a quick link-check and appends the
   dnl results to QT_LIBS.
   BITCOIN_QT_CHECK([
@@ -113,53 +112,40 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
   TEMP_CXXFLAGS=$CXXFLAGS
   CPPFLAGS="$QT_INCLUDES $CPPFLAGS"
   CXXFLAGS="$PIC_FLAGS $CXXFLAGS"
-  if test "x$bitcoin_qt_got_major_vers" = x5; then
+  _BITCOIN_QT_IS_STATIC
-    _BITCOIN_QT_IS_STATIC
+  if test "x$bitcoin_cv_static_qt" = xyes; then
-    if test "x$bitcoin_cv_static_qt" = xyes; then
+    _BITCOIN_QT_FIND_STATIC_PLUGINS
-      _BITCOIN_QT_FIND_STATIC_PLUGINS
+    AC_DEFINE(QT_STATICPLUGIN, 1, [Define this symbol if qt plugins are static])
-      AC_DEFINE(QT_STATICPLUGIN, 1, [Define this symbol if qt plugins are static])
+    AC_CACHE_CHECK(for Qt < 5.4, bitcoin_cv_need_acc_widget,[
-      AC_CACHE_CHECK(for Qt < 5.4, bitcoin_cv_need_acc_widget,[
+      AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+          #include <QtCore/qconfig.h>
-            #include <QtCore/qconfig.h>
+          #ifndef QT_VERSION
-            #ifndef QT_VERSION
+          #  include <QtCore/qglobal.h>
-            #  include <QtCore/qglobal.h>
+          #endif
-            #endif
+        ]],
-          ]],
+        [[
-          [[
+          #if QT_VERSION >= 0x050400
-            #if QT_VERSION >= 0x050400
+          choke
-            choke
+          #endif
-            #endif
+        ]])],
-          ]])],
+      [bitcoin_cv_need_acc_widget=yes],
-        [bitcoin_cv_need_acc_widget=yes],
+      [bitcoin_cv_need_acc_widget=no])
-        [bitcoin_cv_need_acc_widget=no])
+    ])
-      ])
+    if test "x$bitcoin_cv_need_acc_widget" = xyes; then
-      if test "x$bitcoin_cv_need_acc_widget" = xyes; then
+      _BITCOIN_QT_CHECK_STATIC_PLUGINS([Q_IMPORT_PLUGIN(AccessibleFactory)], [-lqtaccessiblewidgets])
-        _BITCOIN_QT_CHECK_STATIC_PLUGINS([Q_IMPORT_PLUGIN(AccessibleFactory)], [-lqtaccessiblewidgets])
-      fi
-      _BITCOIN_QT_CHECK_STATIC_PLUGINS([Q_IMPORT_PLUGIN(QMinimalIntegrationPlugin)],[-lqminimal])
-      AC_DEFINE(QT_QPA_PLATFORM_MINIMAL, 1, [Define this symbol if the minimal qt platform exists])
-      if test "x$TARGET_OS" = xwindows; then
-        _BITCOIN_QT_CHECK_STATIC_PLUGINS([Q_IMPORT_PLUGIN(QWindowsIntegrationPlugin)],[-lqwindows])
-        AC_DEFINE(QT_QPA_PLATFORM_WINDOWS, 1, [Define this symbol if the qt platform is windows])
-      elif test "x$TARGET_OS" = xlinux; then
-        _BITCOIN_QT_CHECK_STATIC_PLUGINS([Q_IMPORT_PLUGIN(QXcbIntegrationPlugin)],[-lqxcb -lxcb-static])
-        AC_DEFINE(QT_QPA_PLATFORM_XCB, 1, [Define this symbol if the qt platform is xcb])
-      elif test "x$TARGET_OS" = xdarwin; then
-        AX_CHECK_LINK_FLAG([[-framework IOKit]],[QT_LIBS="$QT_LIBS -framework IOKit"],[AC_MSG_ERROR(could not iokit framework)])
-        _BITCOIN_QT_CHECK_STATIC_PLUGINS([Q_IMPORT_PLUGIN(QCocoaIntegrationPlugin)],[-lqcocoa])
-        AC_DEFINE(QT_QPA_PLATFORM_COCOA, 1, [Define this symbol if the qt platform is cocoa])
-      fi
     fi
-  else
+    _BITCOIN_QT_CHECK_STATIC_PLUGINS([Q_IMPORT_PLUGIN(QMinimalIntegrationPlugin)],[-lqminimal])
+    AC_DEFINE(QT_QPA_PLATFORM_MINIMAL, 1, [Define this symbol if the minimal qt platform exists])
     if test "x$TARGET_OS" = xwindows; then
-      AC_DEFINE(QT_STATICPLUGIN, 1, [Define this symbol if qt plugins are static])
+      _BITCOIN_QT_CHECK_STATIC_PLUGINS([Q_IMPORT_PLUGIN(QWindowsIntegrationPlugin)],[-lqwindows])
-      _BITCOIN_QT_CHECK_STATIC_PLUGINS([
+      AC_DEFINE(QT_QPA_PLATFORM_WINDOWS, 1, [Define this symbol if the qt platform is windows])
-         Q_IMPORT_PLUGIN(qcncodecs)
+    elif test "x$TARGET_OS" = xlinux; then
-         Q_IMPORT_PLUGIN(qjpcodecs)
+      _BITCOIN_QT_CHECK_STATIC_PLUGINS([Q_IMPORT_PLUGIN(QXcbIntegrationPlugin)],[-lqxcb -lxcb-static])
-         Q_IMPORT_PLUGIN(qtwcodecs)
+      AC_DEFINE(QT_QPA_PLATFORM_XCB, 1, [Define this symbol if the qt platform is xcb])
-         Q_IMPORT_PLUGIN(qkrcodecs)
+    elif test "x$TARGET_OS" = xdarwin; then
-         Q_IMPORT_PLUGIN(AccessibleFactory)],
+      AX_CHECK_LINK_FLAG([[-framework IOKit]],[QT_LIBS="$QT_LIBS -framework IOKit"],[AC_MSG_ERROR(could not iokit framework)])
-         [-lqcncodecs -lqjpcodecs -lqtwcodecs -lqkrcodecs -lqtaccessiblewidgets])
+      _BITCOIN_QT_CHECK_STATIC_PLUGINS([Q_IMPORT_PLUGIN(QCocoaIntegrationPlugin)],[-lqcocoa])
+      AC_DEFINE(QT_QPA_PLATFORM_COCOA, 1, [Define this symbol if the qt platform is cocoa])
     fi
   fi
   CPPFLAGS=$TEMP_CPPFLAGS
@@ -167,9 +153,7 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
   ])
 
   if test "x$use_pkgconfig$qt_bin_path" = xyes; then
-    if test "x$bitcoin_qt_got_major_vers" = x5; then
+    qt_bin_path="`$PKG_CONFIG --variable=host_bins Qt5Core 2>/dev/null`"
-      qt_bin_path="`$PKG_CONFIG --variable=host_bins Qt5Core 2>/dev/null`"
-    fi
   fi
 
   if test "x$use_hardening" != xno; then
@@ -219,11 +203,11 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
     ])
   fi
 
-  BITCOIN_QT_PATH_PROGS([MOC], [moc-qt${bitcoin_qt_got_major_vers} moc${bitcoin_qt_got_major_vers} moc], $qt_bin_path)
+  BITCOIN_QT_PATH_PROGS([MOC], [moc-qt5 moc5 moc], $qt_bin_path)
-  BITCOIN_QT_PATH_PROGS([UIC], [uic-qt${bitcoin_qt_got_major_vers} uic${bitcoin_qt_got_major_vers} uic], $qt_bin_path)
+  BITCOIN_QT_PATH_PROGS([UIC], [uic-qt5 uic5 uic], $qt_bin_path)
-  BITCOIN_QT_PATH_PROGS([RCC], [rcc-qt${bitcoin_qt_got_major_vers} rcc${bitcoin_qt_got_major_vers} rcc], $qt_bin_path)
+  BITCOIN_QT_PATH_PROGS([RCC], [rcc-qt5 rcc5 rcc], $qt_bin_path)
-  BITCOIN_QT_PATH_PROGS([LRELEASE], [lrelease-qt${bitcoin_qt_got_major_vers} lrelease${bitcoin_qt_got_major_vers} lrelease], $qt_bin_path)
+  BITCOIN_QT_PATH_PROGS([LRELEASE], [lrelease-qt5 lrelease5 lrelease], $qt_bin_path)
-  BITCOIN_QT_PATH_PROGS([LUPDATE], [lupdate-qt${bitcoin_qt_got_major_vers} lupdate${bitcoin_qt_got_major_vers} lupdate],$qt_bin_path, yes)
+  BITCOIN_QT_PATH_PROGS([LUPDATE], [lupdate-qt5 lupdate5 lupdate],$qt_bin_path, yes)
 
   BITCOIN_QT_CHECK([
     AC_CACHE_CHECK([whether $RCC accepts --format-version option],
@@ -277,7 +261,7 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
   ],[
     bitcoin_enable_qt=no
   ])
-  AC_MSG_RESULT([$bitcoin_enable_qt (Qt${bitcoin_qt_got_major_vers})])
+  AC_MSG_RESULT([$bitcoin_enable_qt (Qt5)])
 
   AC_SUBST(QT_PIE_FLAGS)
   AC_SUBST(QT_INCLUDES)
@@ -287,7 +271,7 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
   AC_SUBST(QT_DBUS_LIBS)
   AC_SUBST(QT_TEST_INCLUDES)
   AC_SUBST(QT_TEST_LIBS)
-  AC_SUBST(QT_SELECT, qt${bitcoin_qt_got_major_vers})
+  AC_SUBST(QT_SELECT, qt5)
   AC_SUBST(MOC_DEFS)
 ])
 
@@ -316,7 +300,7 @@ AC_DEFUN([_BITCOIN_QT_CHECK_QT5],[
 ])])
 
 dnl Internal. Check if the linked version of Qt was built as static libs.
-dnl Requires: Qt5. This check cannot determine if Qt4 is static.
+dnl Requires: Qt5.
 dnl Requires: INCLUDES and LIBS must be populated as necessary.
 dnl Output: bitcoin_cv_static_qt=yes|no
 dnl Output: Defines QT_STATICPLUGIN if plugins are static.
@@ -361,58 +345,50 @@ AC_DEFUN([_BITCOIN_QT_CHECK_STATIC_PLUGINS],[
 ])
 
 dnl Internal. Find paths necessary for linking qt static plugins
-dnl Inputs: bitcoin_qt_got_major_vers. 4 or 5.
 dnl Inputs: qt_plugin_path. optional.
 dnl Outputs: QT_LIBS is appended
 AC_DEFUN([_BITCOIN_QT_FIND_STATIC_PLUGINS],[
-  if test "x$bitcoin_qt_got_major_vers" = x5; then
+    if test "x$qt_plugin_path" != x; then
-      if test "x$qt_plugin_path" != x; then
+      QT_LIBS="$QT_LIBS -L$qt_plugin_path/platforms"
-        QT_LIBS="$QT_LIBS -L$qt_plugin_path/platforms"
+      if test -d "$qt_plugin_path/accessible"; then
-        if test -d "$qt_plugin_path/accessible"; then
+        QT_LIBS="$QT_LIBS -L$qt_plugin_path/accessible"
-          QT_LIBS="$QT_LIBS -L$qt_plugin_path/accessible"
-        fi
       fi
-     if test "x$use_pkgconfig" = xyes; then
+    fi
-     : dnl
+   if test "x$use_pkgconfig" = xyes; then
-     m4_ifdef([PKG_CHECK_MODULES],[
+   : dnl
-       PKG_CHECK_MODULES([QTPLATFORM], [Qt5PlatformSupport], [QT_LIBS="$QTPLATFORM_LIBS $QT_LIBS"])
+   m4_ifdef([PKG_CHECK_MODULES],[
-       if test "x$TARGET_OS" = xlinux; then
+     PKG_CHECK_MODULES([QTPLATFORM], [Qt5PlatformSupport], [QT_LIBS="$QTPLATFORM_LIBS $QT_LIBS"])
-         PKG_CHECK_MODULES([X11XCB], [x11-xcb], [QT_LIBS="$X11XCB_LIBS $QT_LIBS"])
+     if test "x$TARGET_OS" = xlinux; then
-         if ${PKG_CONFIG} --exists "Qt5Core >= 5.5" 2>/dev/null; then
+       PKG_CHECK_MODULES([X11XCB], [x11-xcb], [QT_LIBS="$X11XCB_LIBS $QT_LIBS"])
-           PKG_CHECK_MODULES([QTXCBQPA], [Qt5XcbQpa], [QT_LIBS="$QTXCBQPA_LIBS $QT_LIBS"])
+       if ${PKG_CONFIG} --exists "Qt5Core >= 5.5" 2>/dev/null; then
-         fi
+         PKG_CHECK_MODULES([QTXCBQPA], [Qt5XcbQpa], [QT_LIBS="$QTXCBQPA_LIBS $QT_LIBS"])
-       elif test "x$TARGET_OS" = xdarwin; then
-         PKG_CHECK_MODULES([QTPRINT], [Qt5PrintSupport], [QT_LIBS="$QTPRINT_LIBS $QT_LIBS"])
        fi
-     ])
+     elif test "x$TARGET_OS" = xdarwin; then
-     else
+       PKG_CHECK_MODULES([QTPRINT], [Qt5PrintSupport], [QT_LIBS="$QTPRINT_LIBS $QT_LIBS"])
-       if test "x$TARGET_OS" = xwindows; then
+     fi
-         AC_CACHE_CHECK(for Qt >= 5.6, bitcoin_cv_need_platformsupport,[
+   ])
-           AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+   else
-               #include <QtCore/qconfig.h>
+     if test "x$TARGET_OS" = xwindows; then
-               #ifndef QT_VERSION
+       AC_CACHE_CHECK(for Qt >= 5.6, bitcoin_cv_need_platformsupport,[
-               #  include <QtCore/qglobal.h>
+         AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-               #endif
+             #include <QtCore/qconfig.h>
-             ]],
+             #ifndef QT_VERSION
-             [[
+             #  include <QtCore/qglobal.h>
-               #if QT_VERSION < 0x050600
+             #endif
-               choke
+           ]],
-               #endif
+           [[
-             ]])],
+             #if QT_VERSION < 0x050600
-           [bitcoin_cv_need_platformsupport=yes],
+             choke
-           [bitcoin_cv_need_platformsupport=no])
+             #endif
-         ])
+           ]])],
-         if test "x$bitcoin_cv_need_platformsupport" = xyes; then
+         [bitcoin_cv_need_platformsupport=yes],
-           BITCOIN_QT_CHECK(AC_CHECK_LIB([${QT_LIB_PREFIX}PlatformSupport],[main],,BITCOIN_QT_FAIL(lib${QT_LIB_PREFIX}PlatformSupport not found)))
+         [bitcoin_cv_need_platformsupport=no])
-         fi
+       ])
+       if test "x$bitcoin_cv_need_platformsupport" = xyes; then
+         BITCOIN_QT_CHECK(AC_CHECK_LIB([${QT_LIB_PREFIX}PlatformSupport],[main],,BITCOIN_QT_FAIL(lib${QT_LIB_PREFIX}PlatformSupport not found)))
        fi
      fi
-  else
+   fi
-    if test "x$qt_plugin_path" != x; then
-      QT_LIBS="$QT_LIBS -L$qt_plugin_path/accessible"
-      QT_LIBS="$QT_LIBS -L$qt_plugin_path/codecs"
-    fi
-  fi
 ])
 
 dnl Internal. Find Qt libraries using pkg-config.
@@ -421,38 +397,14 @@ dnl         first.
 dnl Inputs: $1: If bitcoin_qt_want_version is "auto", check for this version
 dnl         first.
 dnl Outputs: All necessary QT_* variables are set.
-dnl Outputs: bitcoin_qt_got_major_vers is set to "4" or "5".
 dnl Outputs: have_qt_test and have_qt_dbus are set (if applicable) to yes|no.
 AC_DEFUN([_BITCOIN_QT_FIND_LIBS_WITH_PKGCONFIG],[
   m4_ifdef([PKG_CHECK_MODULES],[
-  auto_priority_version=$1
+    QT_LIB_PREFIX=Qt5
-  if test "x$auto_priority_version" = x; then
-    auto_priority_version=qt5
-  fi
-    if test "x$bitcoin_qt_want_version" = xqt5 ||  ( test "x$bitcoin_qt_want_version" = xauto && test "x$auto_priority_version" = xqt5 ); then
-      QT_LIB_PREFIX=Qt5
-      bitcoin_qt_got_major_vers=5
-    else
-      QT_LIB_PREFIX=Qt
-      bitcoin_qt_got_major_vers=4
-    fi
     qt5_modules="Qt5Core Qt5Gui Qt5Network Qt5Widgets"
-    qt4_modules="QtCore QtGui QtNetwork"
     BITCOIN_QT_CHECK([
-      if test "x$bitcoin_qt_want_version" = xqt5 || ( test "x$bitcoin_qt_want_version" = xauto && test "x$auto_priority_version" = xqt5 ); then
+      PKG_CHECK_MODULES([QT5], [$qt5_modules], [QT_INCLUDES="$QT5_CFLAGS"; QT_LIBS="$QT5_LIBS" have_qt=yes],[have_qt=no])
-        PKG_CHECK_MODULES([QT5], [$qt5_modules], [QT_INCLUDES="$QT5_CFLAGS"; QT_LIBS="$QT5_LIBS" have_qt=yes],[have_qt=no])
-      elif test "x$bitcoin_qt_want_version" = xqt4 || ( test "x$bitcoin_qt_want_version" = xauto && test "x$auto_priority_version" = xqt4 ); then
-        PKG_CHECK_MODULES([QT4], [$qt4_modules], [QT_INCLUDES="$QT4_CFLAGS"; QT_LIBS="$QT4_LIBS" ; have_qt=yes], [have_qt=no])
-      fi
 
-      dnl qt version is set to 'auto' and the preferred version wasn't found. Now try the other.
-      if test "x$have_qt" = xno && test "x$bitcoin_qt_want_version" = xauto; then
-        if test "x$auto_priority_version" = xqt5; then
-          PKG_CHECK_MODULES([QT4], [$qt4_modules], [QT_INCLUDES="$QT4_CFLAGS"; QT_LIBS="$QT4_LIBS" ; have_qt=yes; QT_LIB_PREFIX=Qt; bitcoin_qt_got_major_vers=4], [have_qt=no])
-        else
-          PKG_CHECK_MODULES([QT5], [$qt5_modules], [QT_INCLUDES="$QT5_CFLAGS"; QT_LIBS="$QT5_LIBS" ; have_qt=yes; QT_LIB_PREFIX=Qt5; bitcoin_qt_got_major_vers=5], [have_qt=no])
-        fi
-      fi
       if test "x$have_qt" != xyes; then
         have_qt=no
         BITCOIN_QT_FAIL([Qt dependencies not found])
@@ -473,7 +425,6 @@ dnl from the discovered headers.
 dnl Inputs: bitcoin_qt_want_version (from --with-gui=). The version to use.
 dnl         If "auto", the version will be discovered by _BITCOIN_QT_CHECK_QT5.
 dnl Outputs: All necessary QT_* variables are set.
-dnl Outputs: bitcoin_qt_got_major_vers is set to "4" or "5".
 dnl Outputs: have_qt_test and have_qt_dbus are set (if applicable) to yes|no.
 AC_DEFUN([_BITCOIN_QT_FIND_LIBS_WITHOUT_PKGCONFIG],[
   TEMP_CPPFLAGS="$CPPFLAGS"
@@ -495,13 +446,7 @@ AC_DEFUN([_BITCOIN_QT_FIND_LIBS_WITHOUT_PKGCONFIG],[
     if test "x$bitcoin_qt_want_version" = xauto; then
       _BITCOIN_QT_CHECK_QT5
     fi
-    if test "x$bitcoin_cv_qt5" = xyes || test "x$bitcoin_qt_want_version" = xqt5; then
+    QT_LIB_PREFIX=Qt5
-      QT_LIB_PREFIX=Qt5
-      bitcoin_qt_got_major_vers=5
-    else
-      QT_LIB_PREFIX=Qt
-      bitcoin_qt_got_major_vers=4
-    fi
   ])
 
   BITCOIN_QT_CHECK([
@@ -523,9 +468,7 @@ AC_DEFUN([_BITCOIN_QT_FIND_LIBS_WITHOUT_PKGCONFIG],[
   BITCOIN_QT_CHECK(AC_CHECK_LIB([${QT_LIB_PREFIX}Core]   ,[main],,BITCOIN_QT_FAIL(lib${QT_LIB_PREFIX}Core not found)))
   BITCOIN_QT_CHECK(AC_CHECK_LIB([${QT_LIB_PREFIX}Gui]    ,[main],,BITCOIN_QT_FAIL(lib${QT_LIB_PREFIX}Gui not found)))
   BITCOIN_QT_CHECK(AC_CHECK_LIB([${QT_LIB_PREFIX}Network],[main],,BITCOIN_QT_FAIL(lib${QT_LIB_PREFIX}Network not found)))
-  if test "x$bitcoin_qt_got_major_vers" = x5; then
+  BITCOIN_QT_CHECK(AC_CHECK_LIB([${QT_LIB_PREFIX}Widgets],[main],,BITCOIN_QT_FAIL(lib${QT_LIB_PREFIX}Widgets not found)))
-    BITCOIN_QT_CHECK(AC_CHECK_LIB([${QT_LIB_PREFIX}Widgets],[main],,BITCOIN_QT_FAIL(lib${QT_LIB_PREFIX}Widgets not found)))
-  fi
   QT_LIBS="$LIBS"
   LIBS="$TEMP_LIBS"
 
@@ -551,4 +494,3 @@ AC_DEFUN([_BITCOIN_QT_FIND_LIBS_WITHOUT_PKGCONFIG],[
   CXXFLAGS="$TEMP_CXXFLAGS"
   LIBS="$TEMP_LIBS"
 ])
-

configure.ac

@@ -165,7 +165,7 @@ AC_ARG_ENABLE([lcov],
   [enable lcov testing (default is no)])],
   [use_lcov=$enableval],
   [use_lcov=no])
-  
+
 AC_ARG_ENABLE([lcov-branch-coverage],
   [AS_HELP_STRING([--enable-lcov-branch-coverage],
   [enable lcov testing branch coverage (default is no)])],
@@ -856,7 +856,7 @@ fi
 BITCOIN_QT_INIT
 
 dnl sets $bitcoin_enable_qt, $bitcoin_enable_qt_test, $bitcoin_enable_qt_dbus
-BITCOIN_QT_CONFIGURE([$use_pkgconfig], [qt5])
+BITCOIN_QT_CONFIGURE([$use_pkgconfig])
 
 if test x$build_bitcoin_utils$build_bitcoind$bitcoin_enable_qt$use_tests$use_bench = xnonononono; then
     use_boost=no
@@ -1442,12 +1442,11 @@ case ${OS} in
    ;;
 esac
 
-echo 
+echo
 echo "Options used to compile and link:"
 echo "  with wallet         = $enable_wallet"
 echo "  with gui / qt       = $bitcoin_enable_qt"
 if test x$bitcoin_enable_qt != xno; then
-    echo "    qt version        = $bitcoin_qt_got_major_vers"
     echo "    with qr           = $use_qr"
 fi
 echo "  with zmq            = $use_zmq"
@@ -1459,7 +1458,7 @@ echo "  debug enabled       = $enable_debug"
 echo "  crash hooks enabled = $enable_crashhooks"
 echo "  miner enabled       = $enable_miner"
 echo "  werror              = $enable_werror"
-echo 
+echo
 echo "  target os           = $TARGET_OS"
 echo "  build os            = $BUILD_OS"
 echo
@@ -1470,4 +1469,4 @@ echo "  CXX                 = $CXX"
 echo "  CXXFLAGS            = $CXXFLAGS"
 echo "  LDFLAGS             = $LDFLAGS"
 echo "  ARFLAGS             = $ARFLAGS"
-echo 
+echo

src/qt/addressbookpage.cpp

@@ -141,13 +141,8 @@ void AddressBookPage::setModel(AddressTableModel *_model)
     ui->tableView->sortByColumn(0, Qt::AscendingOrder);
 
     // Set column widths
-#if QT_VERSION < 0x050000
-    ui->tableView->horizontalHeader()->setResizeMode(AddressTableModel::Label, QHeaderView::Stretch);
-    ui->tableView->horizontalHeader()->setResizeMode(AddressTableModel::Address, QHeaderView::ResizeToContents);
-#else
     ui->tableView->horizontalHeader()->setSectionResizeMode(AddressTableModel::Label, QHeaderView::Stretch);
     ui->tableView->horizontalHeader()->setSectionResizeMode(AddressTableModel::Address, QHeaderView::ResizeToContents);
-#endif
 
     connect(ui->tableView->selectionModel(), SIGNAL(selectionChanged(QItemSelection,QItemSelection)),
         this, SLOT(selectionChanged()));

src/qt/bantablemodel.cpp

@@ -52,9 +52,7 @@ public:
             g_connman->GetBanned(banMap);
 
         cachedBanlist.clear();
-#if QT_VERSION >= 0x040700
         cachedBanlist.reserve(banMap.size());
-#endif
         for (const auto& entry : banMap)
         {
             CCombinedBan banEntry;

src/qt/bitcoingui.cpp

@@ -55,14 +55,8 @@
 #include <QStyle>
 #include <QTimer>
 #include <QToolBar>
-#include <QVBoxLayout>
-
-#if QT_VERSION < 0x050000
-#include <QTextDocument>
-#include <QUrl>
-#else
 #include <QUrlQuery>
-#endif
+#include <QVBoxLayout>
 
 const std::string BitcoinGUI::DEFAULT_UIPLATFORM =
 #if defined(Q_OS_MAC)
@@ -152,12 +146,6 @@ BitcoinGUI::BitcoinGUI(const PlatformStyle *_platformStyle, const NetworkStyle *
     setWindowIcon(networkStyle->getTrayAndWindowIcon());
     setWindowTitle(windowTitle);
 
-#if defined(Q_OS_MAC) && QT_VERSION < 0x050000
-    // This property is not implemented in Qt 5. Setting it has no effect.
-    // A replacement API (QtMacUnifiedToolBar) is available in QtMacExtras.
-    setUnifiedTitleAndToolBarOnMac(true);
-#endif
-
     rpcConsole = new RPCConsole(_platformStyle, 0);
     helpMessageDialog = new HelpMessageDialog(this, HelpMessageDialog::cmdline);
 #ifdef ENABLE_WALLET
@@ -232,7 +220,7 @@ BitcoinGUI::BitcoinGUI(const PlatformStyle *_platformStyle, const NetworkStyle *
 
     // Override style sheet for progress bar for styles that have a segmented progress bar,
     // as they make the text unreadable (workaround for issue #1071)
-    // See https://qt-project.org/doc/qt-4.8/gallery.html
+    // See https://doc.qt.io/qt-5/gallery.html
     QString curStyle = QApplication::style()->metaObject()->className();
     if(curStyle == "QWindowsStyle" || curStyle == "QWindowsXPStyle")
     {

src/qt/coincontroldialog.cpp

@@ -114,11 +114,7 @@ CoinControlDialog::CoinControlDialog(const PlatformStyle *_platformStyle, QWidge
     connect(ui->treeWidget, SIGNAL(itemChanged(QTreeWidgetItem*, int)), this, SLOT(viewItemChanged(QTreeWidgetItem*, int)));
 
     // click on header
-#if QT_VERSION < 0x050000
-    ui->treeWidget->header()->setClickable(true);
-#else
     ui->treeWidget->header()->setSectionsClickable(true);
-#endif
     connect(ui->treeWidget->header(), SIGNAL(sectionClicked(int)), this, SLOT(headerSectionClicked(int)));
 
     // ok button

src/qt/dash.cpp

@@ -59,13 +59,6 @@
 
 #if defined(QT_STATICPLUGIN)
 #include <QtPlugin>
-#if QT_VERSION < 0x050000
-Q_IMPORT_PLUGIN(qcncodecs)
-Q_IMPORT_PLUGIN(qjpcodecs)
-Q_IMPORT_PLUGIN(qtwcodecs)
-Q_IMPORT_PLUGIN(qkrcodecs)
-Q_IMPORT_PLUGIN(qtaccessiblewidgets)
-#else
 #if QT_VERSION < 0x050400
 Q_IMPORT_PLUGIN(AccessibleFactory)
 #endif
@@ -77,11 +70,6 @@ Q_IMPORT_PLUGIN(QWindowsIntegrationPlugin);
 Q_IMPORT_PLUGIN(QCocoaIntegrationPlugin);
 #endif
 #endif
-#endif
-
-#if QT_VERSION < 0x050000
-#include <QTextCodec>
-#endif
 
 // Declare meta types used for QMetaObject::invokeMethod
 Q_DECLARE_METATYPE(bool*)
@@ -154,16 +142,6 @@ static void initTranslations(QTranslator &qtTranslatorBase, QTranslator &qtTrans
 }
 
 /* qDebug() message handler --> debug.log */
-#if QT_VERSION < 0x050000
-void DebugMessageHandler(QtMsgType type, const char *msg)
-{
-    if (type == QtDebugMsg) {
-        LogPrint(BCLog::QT, "GUI: %s\n", msg);
-    } else {
-        LogPrintf("GUI: %s\n", msg);
-    }
-}
-#else
 void DebugMessageHandler(QtMsgType type, const QMessageLogContext& context, const QString &msg)
 {
     Q_UNUSED(context);
@@ -173,7 +151,6 @@ void DebugMessageHandler(QtMsgType type, const QMessageLogContext& context, cons
         LogPrintf("GUI: %s\n", msg.toStdString());
     }
 }
-#endif
 
 /** Class encapsulating Dash Core startup and shutdown.
  * Allows running startup and shutdown in a different thread from the UI thread.
@@ -589,13 +566,7 @@ int main(int argc, char *argv[])
 
     // Do not refer to data directory yet, this can be overridden by Intro::pickDataDirectory
 
-    /// 2. Basic Qt initialization (not dependent on parameters or configuration)
+    /// 1. Basic Qt initialization (not dependent on parameters or configuration)
-#if QT_VERSION < 0x050000
-    // Internal string conversion is all UTF-8
-    QTextCodec::setCodecForTr(QTextCodec::codecForName("UTF-8"));
-    QTextCodec::setCodecForCStrings(QTextCodec::codecForTr());
-#endif
-
     Q_INIT_RESOURCE(dash);
     Q_INIT_RESOURCE(dash_locale);
 
@@ -718,17 +689,12 @@ int main(int argc, char *argv[])
     /// 9. Main GUI initialization
     // Install global event filter that makes sure that long tooltips can be word-wrapped
     app.installEventFilter(new GUIUtil::ToolTipToRichTextFilter(TOOLTIP_WRAP_THRESHOLD, &app));
-#if QT_VERSION < 0x050000
-    // Install qDebug() message handler to route to debug.log
-    qInstallMsgHandler(DebugMessageHandler);
-#else
 #if defined(Q_OS_WIN)
     // Install global event filter for processing Windows session related Windows messages (WM_QUERYENDSESSION and WM_ENDSESSION)
     qApp->installNativeEventFilter(new WinShutdownMonitor());
 #endif
     // Install qDebug() message handler to route to debug.log
     qInstallMessageHandler(DebugMessageHandler);
-#endif
     // Allow parameter interaction before we create the options model
     app.parameterSetup();
     // Load GUI settings from QSettings
@@ -749,7 +715,7 @@ int main(int argc, char *argv[])
         // so the GUI thread won't be held up.
         if (BitcoinCore::baseInitialize()) {
             app.requestInitialize();
-#if defined(Q_OS_WIN) && QT_VERSION >= 0x050000
+#if defined(Q_OS_WIN)
             WinShutdownMonitor::registerShutdownBlockReason(QObject::tr("%1 didn't yet exit safely...").arg(QObject::tr(PACKAGE_NAME)), (HWND)app.getMainWinId());
 #endif
             app.exec();

src/qt/guiutil.cpp

@@ -51,13 +51,9 @@
 #include <QSettings>
 #include <QTextDocument> // for Qt::mightBeRichText
 #include <QThread>
+#include <QUrlQuery>
 #include <QMouseEvent>
 
-#if QT_VERSION < 0x050000
-#include <QUrl>
-#else
-#include <QUrlQuery>
-#endif
 
 #if QT_VERSION >= 0x50200
 #include <QFontDatabase>
@@ -158,11 +154,7 @@ QFont fixedPitchFont()
     return QFontDatabase::systemFont(QFontDatabase::FixedFont);
 #else
     QFont font("Monospace");
-#if QT_VERSION >= 0x040800
     font.setStyleHint(QFont::Monospace);
-#else
-    font.setStyleHint(QFont::TypeWriter);
-#endif
     return font;
 #endif
 }
@@ -190,12 +182,10 @@ void setupAddressWidget(QValidatedLineEdit *widget, QWidget *parent, bool fAllow
     parent->setFocusProxy(widget);
 
     widget->setFont(fixedPitchFont());
-#if QT_VERSION >= 0x040700
     // We don't want translators to use own addresses in translations
     // and this is the only place, where this address is supplied.
     widget->setPlaceholderText(QObject::tr("Enter a Dash address (e.g. %1)").arg(
         QString::fromStdString(DummyAddress(Params()))));
-#endif
     widget->setValidator(new BitcoinAddressEntryValidator(parent, fAllowURI));
     widget->setCheckValidator(new BitcoinAddressCheckValidator(parent));
 }
@@ -223,12 +213,8 @@ bool parseBitcoinURI(const QUrl &uri, SendCoinsRecipient *out)
     }
     rv.amount = 0;
 
-#if QT_VERSION < 0x050000
-    QList<QPair<QString, QString> > items = uri.queryItems();
-#else
     QUrlQuery uriQuery(uri);
     QList<QPair<QString, QString> > items = uriQuery.queryItems();
-#endif
 
     for (QList<QPair<QString, QString> >::iterator i = items.begin(); i != items.end(); i++)
     {
@@ -334,11 +320,7 @@ bool isDust(const QString& address, const CAmount& amount)
 
 QString HtmlEscape(const QString& str, bool fMultiLine)
 {
-#if QT_VERSION < 0x050000
-    QString escaped = Qt::escape(str);
-#else
     QString escaped = str.toHtmlEscaped();
-#endif
     escaped = escaped.replace(" ", "&nbsp;");
     if(fMultiLine)
     {
@@ -380,11 +362,7 @@ QString getSaveFileName(QWidget *parent, const QString &caption, const QString &
     QString myDir;
     if(dir.isEmpty()) // Default to user documents location
     {
-#if QT_VERSION < 0x050000
-        myDir = QDesktopServices::storageLocation(QDesktopServices::DocumentsLocation);
-#else
         myDir = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
-#endif
     }
     else
     {
@@ -430,11 +408,7 @@ QString getOpenFileName(QWidget *parent, const QString &caption, const QString &
     QString myDir;
     if(dir.isEmpty()) // Default to user documents location
     {
-#if QT_VERSION < 0x050000
-        myDir = QDesktopServices::storageLocation(QDesktopServices::DocumentsLocation);
-#else
         myDir = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
-#endif
     }
     else
     {
@@ -611,11 +585,7 @@ void TableViewLastColumnResizingFixer::disconnectViewHeadersSignals()
 // Refactored here for readability.
 void TableViewLastColumnResizingFixer::setViewHeaderResizeMode(int logicalIndex, QHeaderView::ResizeMode resizeMode)
 {
-#if QT_VERSION < 0x050000
-    tableView->horizontalHeader()->setResizeMode(logicalIndex, resizeMode);
-#else
     tableView->horizontalHeader()->setSectionResizeMode(logicalIndex, resizeMode);
-#endif
 }
 
 void TableViewLastColumnResizingFixer::resizeColumn(int nColumnIndex, int width)

src/qt/guiutil.h

@@ -283,7 +283,7 @@ namespace GUIUtil
         void mouseReleaseEvent(QMouseEvent *event);
     };
 
-#if defined(Q_OS_MAC) && QT_VERSION >= 0x050000
+#if defined(Q_OS_MAC)
     // workaround for Qt OSX Bug:
     // https://bugreports.qt-project.org/browse/QTBUG-15631
     // QProgressBar uses around 10% CPU even when app is in background

src/qt/macdockiconhandler.mm

@@ -7,10 +7,6 @@
 #include <AppKit/AppKit.h>
 #include <objc/runtime.h>
 
-#if QT_VERSION < 0x050000
-extern void qt_mac_set_dock_menu(QMenu *);
-#endif
-
 static MacDockIconHandler *s_instance = nullptr;
 
 bool dockClickHandler(id self, SEL _cmd, ...) {

src/qt/networkstyle.cpp

@@ -85,13 +85,8 @@ NetworkStyle::NetworkStyle(const QString &_appName, const int iconColorHueShift,
         rotateColors(splashImageImg, iconColorHueShift, iconColorSaturationReduction);
 
         //convert back to QPixmap
-#if QT_VERSION >= 0x040700
         appIconPixmap.convertFromImage(appIconImg);
         splashImagePixmap.convertFromImage(splashImageImg);
-#else
-        appIconPixmap = QPixmap::fromImage(appIconImg);
-        splashImagePixmap = QPixmap::fromImage(splashImageImg);
-#endif
     }
 
     appIcon             = QIcon(appIconPixmap);

src/qt/openuridialog.cpp

@@ -16,9 +16,7 @@ OpenURIDialog::OpenURIDialog(QWidget *parent) :
     ui(new Ui::OpenURIDialog)
 {
     ui->setupUi(this);
-#if QT_VERSION >= 0x040700
     ui->uriEdit->setPlaceholderText("dash:");
-#endif
 }
 
 OpenURIDialog::~OpenURIDialog()

src/qt/optionsdialog.cpp

@@ -104,28 +104,16 @@ OptionsDialog::OptionsDialog(QWidget *parent, bool enableWallet) :
         /** check if the locale name consists of 2 parts (language_country) */
         if(langStr.contains("_"))
         {
-#if QT_VERSION >= 0x040800
             /** display language strings as "native language - native country (locale name)", e.g. "Deutsch - Deutschland (de)" */
             ui->lang->addItem(locale.nativeLanguageName() + QString(" - ") + locale.nativeCountryName() + QString(" (") + langStr + QString(")"), QVariant(langStr));
-#else
-            /** display language strings as "language - country (locale name)", e.g. "German - Germany (de)" */
-            ui->lang->addItem(QLocale::languageToString(locale.language()) + QString(" - ") + QLocale::countryToString(locale.country()) + QString(" (") + langStr + QString(")"), QVariant(langStr));
-#endif
         }
         else
         {
-#if QT_VERSION >= 0x040800
             /** display language strings as "native language (locale name)", e.g. "Deutsch (de)" */
             ui->lang->addItem(locale.nativeLanguageName() + QString(" (") + langStr + QString(")"), QVariant(langStr));
-#else
-            /** display language strings as "language (locale name)", e.g. "German (de)" */
-            ui->lang->addItem(QLocale::languageToString(locale.language()) + QString(" (") + langStr + QString(")"), QVariant(langStr));
-#endif
         }
     }
-#if QT_VERSION >= 0x040700
     ui->thirdPartyTxUrls->setPlaceholderText("https://example.com/tx/%s");
-#endif
 
     ui->unit->setModel(new BitcoinUnits(this));
 

src/qt/paymentrequestplus.cpp

@@ -97,12 +97,10 @@ bool PaymentRequestPlus::getMerchant(X509_STORE* certStore, QString& merchant) c
             qWarning() << "PaymentRequestPlus::getMerchant: Payment request: certificate expired or not yet active: " << qCert;
             return false;
         }
-#if QT_VERSION >= 0x050000
         if (qCert.isBlacklisted()) {
             qWarning() << "PaymentRequestPlus::getMerchant: Payment request: certificate blacklisted: " << qCert;
             return false;
         }
-#endif
         const unsigned char *data = (const unsigned char *)certChain.certificate(i).data();
         X509 *cert = d2i_X509(nullptr, &data, certChain.certificate(i).size());
         if (cert)

src/qt/paymentserver.cpp

@@ -41,12 +41,7 @@
 #include <QSslSocket>
 #include <QStringList>
 #include <QTextDocument>
-
-#if QT_VERSION < 0x050000
-#include <QUrl>
-#else
 #include <QUrlQuery>
-#endif
 
 const int BITCOIN_IPC_CONNECT_TIMEOUT = 1000; // milliseconds
 const QString BITCOIN_IPC_PREFIX("dash:");
@@ -100,11 +95,7 @@ static QList<QString> savedPaymentRequests;
 
 static void ReportInvalidCertificate(const QSslCertificate& cert)
 {
-#if QT_VERSION < 0x050000
-    qDebug() << QString("%1: Payment server found an invalid certificate: ").arg(__func__) << cert.serialNumber() << cert.subjectInfo(QSslCertificate::CommonName) << cert.subjectInfo(QSslCertificate::OrganizationalUnitName);
-#else
     qDebug() << QString("%1: Payment server found an invalid certificate: ").arg(__func__) << cert.serialNumber() << cert.subjectInfo(QSslCertificate::CommonName) << cert.subjectInfo(QSslCertificate::DistinguishedNameQualifier) << cert.subjectInfo(QSslCertificate::OrganizationalUnitName);
-#endif
 }
 
 //
@@ -157,13 +148,11 @@ void PaymentServer::LoadRootCAs(X509_STORE* _store)
             continue;
         }
 
-#if QT_VERSION >= 0x050000
         // Blacklisted certificate
         if (cert.isBlacklisted()) {
             ReportInvalidCertificate(cert);
             continue;
         }
-#endif
         QByteArray certData = cert.toDer();
         const unsigned char *data = (const unsigned char *)certData.data();
 
@@ -408,11 +397,7 @@ void PaymentServer::handleURIOrFile(const QString& s)
 
     if (s.startsWith(BITCOIN_IPC_PREFIX, Qt::CaseInsensitive)) // dash: URI
     {
-#if QT_VERSION < 0x050000
-        QUrl uri(s);
-#else
         QUrlQuery uri((QUrl(s)));
-#endif
         if (uri.hasQueryItem("r")) // payment request URI
         {
             QByteArray temp;

src/qt/peertablemodel.cpp

@@ -63,9 +63,7 @@ public:
             std::vector<CNodeStats> vstats;
             if(g_connman)
                 g_connman->GetNodeStats(vstats);
-#if QT_VERSION >= 0x040700
             cachedNodeStats.reserve(vstats.size());
-#endif
             for (const CNodeStats& nodestats : vstats)
             {
                 CNodeCombinedStats stats;

src/qt/receiverequestdialog.cpp

@@ -16,9 +16,6 @@
 #include <QMimeData>
 #include <QMouseEvent>
 #include <QPixmap>
-#if QT_VERSION < 0x050000
-#include <QUrl>
-#endif
 
 #if defined(HAVE_CONFIG_H)
 #include <config/dash-config.h> /* for USE_QRCODE */

src/qt/rpcconsole.cpp

@@ -40,10 +40,6 @@
 #include <QTimer>
 #include <QStringList>
 
-#if QT_VERSION < 0x050000
-#include <QUrl>
-#endif
-
 // TODO: add a scrollback limit, as there is currently none
 // TODO: make it possible to filter out categories (esp debug messages when implemented)
 // TODO: receive errors and debug messages through ClientModel

src/qt/sendcoinsentry.cpp

@@ -27,9 +27,7 @@ SendCoinsEntry::SendCoinsEntry(const PlatformStyle *_platformStyle, QWidget *par
 
     if (platformStyle->getUseExtraSpacing())
         ui->payToLayout->setSpacing(4);
-#if QT_VERSION >= 0x040700
     ui->addAsLabel->setPlaceholderText(tr("Enter a label for this address to add it to your address book"));
-#endif
 
     // These icons are needed on Mac also!
     ui->addressBookButton->setIcon(QIcon(":/icons/address-book"));

src/qt/signverifymessagedialog.cpp

@@ -29,9 +29,7 @@ SignVerifyMessageDialog::SignVerifyMessageDialog(const PlatformStyle *_platformS
 {
     ui->setupUi(this);
 
-#if QT_VERSION >= 0x040700
     ui->signatureOut_SM->setPlaceholderText(tr("Click \"Sign Message\" to generate signature"));
-#endif
 
 #ifdef Q_OS_MAC // Icons on push buttons are very uncommon on Mac
     ui->signMessageButton_SM->setIcon(QIcon());

src/qt/test/test_main.cpp

@@ -27,12 +27,6 @@
 
 #if defined(QT_STATICPLUGIN)
 #include <QtPlugin>
-#if QT_VERSION < 0x050000
-Q_IMPORT_PLUGIN(qcncodecs)
-Q_IMPORT_PLUGIN(qjpcodecs)
-Q_IMPORT_PLUGIN(qtwcodecs)
-Q_IMPORT_PLUGIN(qkrcodecs)
-#else
 #if defined(QT_QPA_PLATFORM_MINIMAL)
 Q_IMPORT_PLUGIN(QMinimalIntegrationPlugin);
 #endif
@@ -44,7 +38,6 @@ Q_IMPORT_PLUGIN(QWindowsIntegrationPlugin);
 Q_IMPORT_PLUGIN(QCocoaIntegrationPlugin);
 #endif
 #endif
-#endif
 
 extern void noui_connect();
 

src/qt/transactionview.cpp

@@ -113,16 +113,12 @@ TransactionView::TransactionView(const PlatformStyle *platformStyle, QWidget *pa
     hlayout->addWidget(typeWidget);
 
     search_widget = new QLineEdit(this);
-#if QT_VERSION >= 0x040700
     search_widget->setPlaceholderText(tr("Enter address, transaction id, or label to search"));
-#endif
     search_widget->setObjectName("search_widget");
     hlayout->addWidget(search_widget);
 
     amountWidget = new QLineEdit(this);
-#if QT_VERSION >= 0x040700
     amountWidget->setPlaceholderText(tr("Min amount"));
-#endif
     if (platformStyle->getUseExtraSpacing()) {
         amountWidget->setFixedWidth(118);
     } else {

src/qt/winshutdownmonitor.cpp

@@ -4,7 +4,7 @@
 
 #include <qt/winshutdownmonitor.h>
 
-#if defined(Q_OS_WIN) && QT_VERSION >= 0x050000
+#if defined(Q_OS_WIN)
 #include <init.h>
 #include <util.h>
 

src/qt/winshutdownmonitor.h

@@ -9,7 +9,6 @@
 #include <QByteArray>
 #include <QString>
 
-#if QT_VERSION >= 0x050000
 #include <windef.h> // for HWND
 
 #include <QAbstractNativeEventFilter>
@@ -24,6 +23,5 @@ public:
     static void registerShutdownBlockReason(const QString& strReason, const HWND& mainWinId);
 };
 #endif
-#endif
 
 #endif // BITCOIN_QT_WINSHUTDOWNMONITOR_H