--- CMakeLists.txt.orig	2017-01-24 21:36:21 UTC
+++ CMakeLists.txt
@@ -25,7 +25,11 @@ if (NOT DEFINED CMAKE_CONFIGURATION_TYPES AND NOT CMAK
 	set (CMAKE_BUILD_TYPE "${default}" CACHE STRING "Choose the type of build, options are: None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used) Debug Release RelWithDebInfo MinSizeRel." FORCE)
 endif ()
 
-# C++14 support, warnings and other flags
+# C++17 support, warnings and other flags
+#
+# 17 is needed for std::optional, in qxmpp
+set (CMAKE_CXX_STANDARD 17)
+set (CMAKE_CXX_STANDARD_REQUIRED ON)
 
 set (DEFINITIONS QT_NO_CAST_TO_ASCII QT_DISABLE_DEPRECATED_BEFORE=0x040900)
 list (APPEND DEFINITIONS KADU_EXPORT_TESTS)
@@ -38,7 +42,6 @@ else ()
 	set (COMMON_COMPILE_FLAGS "-Wall -Wextra -Wundef -Wunused -Wuninitialized -Wcast-align -Wpointer-arith -fno-common")
 	set (C_FLAGS "-Wwrite-strings")
 	set (CXX_FLAGS "-Woverloaded-virtual -Wnon-virtual-dtor ${CXX_FLAGS}")
-	set (CMAKE_CXX_STANDARD 14)
 
 	if (NOT WIN32)
 		set (COMMON_COMPILE_FLAGS "${COMMON_COMPILE_FLAGS} -fvisibility=hidden")