--- a/kadu-core/CMakeLists.txt	
+++ a/kadu-core/CMakeLists.txt	
@@ -212,12 +212,12 @@ endif ()
 message (${ADDITIONAL_LIBKADU_LIBRARIES})
 target_link_libraries (libkadu LINK_PRIVATE ${ADDITIONAL_LIBKADU_LIBRARIES})
 
-find_package (QCA2 REQUIRED)
+find_package (Qca-qt5 REQUIRED)
 
 add_executable (kadu WIN32 ${main_SRCS})
 kadu_set_flags (kadu)
 qt5_use_modules (kadu LINK_PRIVATE Core Gui Widgets Network Xml)
-target_link_libraries (kadu LINK_PRIVATE libkadu ${ADDITIONAL_LIBRARIES} ${QCA2_LIBRARIES})
+target_link_libraries (kadu LINK_PRIVATE libkadu ${ADDITIONAL_LIBRARIES} qca-qt5)
 
 if (NOT IS_ABSOLUTE "${KADU_INSTALL_LIB_DIR}")
 	set (install_full_lib_dir "${CMAKE_INSTALL_PREFIX}/${KADU_INSTALL_LIB_DIR}")
--- a/kadu-core/main.cpp	
+++ a/kadu-core/main.cpp	
@@ -33,7 +33,7 @@ 
 
 #include <QtCore/QLibraryInfo>
 #include <QtCore/QTranslator>
-#include <QtCrypto/QtCrypto>
+#include <QtCrypto>
 #include <QtWidgets/QApplication>
 #include <QtWidgets/QMessageBox>
 
--- a/plugins/qt4_docking/qt4_docking.cpp	
+++ a/plugins/qt4_docking/qt4_docking.cpp	
@@ -26,6 +26,7 @@ 
 #include <QtCore/QEvent>
 #include <QtGui/QMouseEvent>
 #include <QtGui/QMovie>
+#include <QtGui/QIcon>
 
 #include "plugins/docking/docking.h"
 
@@ -68,7 +69,8 @@ Qt4TrayIcon::Qt4TrayIcon(QWidget *parent) :
 {
 	kdebugf();
 
-	setIcon(DockingManager::instance()->defaultIcon().icon());
+	QIcon icon = QIcon::fromTheme(DockingManager::instance()->defaultIcon().fullPath());
+	setIcon(icon);
 
 	connect(this, SIGNAL(activated(QSystemTrayIcon::ActivationReason)), this, SLOT(trayActivated(QSystemTrayIcon::ActivationReason)));
 
@@ -102,7 +104,7 @@ void Qt4TrayIcon::changeTrayIcon(const KaduIcon &icon)
 		Movie->deleteLater();
 		Movie = 0;
 	}
-	setIcon(icon.icon());
+	setIcon(QIcon::fromTheme(icon.fullPath()));
 }
 
 void Qt4TrayIcon::changeTrayMovie(const QString &moviePath)