diff --git a/build/common.prf b/build/common.prf
index 694e2562a..12df1de2f 100644
--- a/build/common.prf
+++ b/build/common.prf
@@ -55,6 +55,7 @@ isEmpty(PYTHONQT_GENERATED_PATH) {
 }
 
 VERSION = 3.2.0
+greaterThan(QT_MAJOR_VERSION, 5) | greaterThan(QT_MINOR_VERSION, 9): CONFIG += c++17 c++11
 win32: CONFIG += skip_target_version_ext
 gcc|win32-clang-msvc:QMAKE_CXXFLAGS += -Wno-deprecated-declarations -Wuninitialized -Winit-self -pedantic
 win32-clang-msvc:QMAKE_CXXFLAGS += -Wno-unused-command-line-argument
diff --git a/build/python.prf b/build/python.prf
index aec051e90..9d61cf109 100644
--- a/build/python.prf
+++ b/build/python.prf
@@ -66,11 +66,10 @@ contains(PKGCONFIG, "python.*"){
   isEmpty(PYTHON_PATH):PYTHON_PATH=$(PYTHON_PATH)
   isEmpty(PYTHON_PATH)|!exists("$$PYTHON_PATH\\include") | !exists("$$PYTHON_PATH\\libs\\") {
      error("PYTHON_PATH must be set to correct folder with \\libs and \\include subfolders ")
-  }
-
-  INCLUDEPATH += $$shell_path($${PYTHON_PATH}/include)
+  }  
+  INCLUDEPATH += $${PYTHON_PATH}/include
 
-  LIBS += $$shell_path(-L$${PYTHON_PATH}/libs)
+  LIBS += -L$${PYTHON_PATH}/libs
   LIBS += -lpython$${PYTHON_VERSION_MAJOR}$${PYTHON_VERSION_MINOR}$${DEBUG_EXT}
 
   # Hack for "CONFIG+=testcase" and 'make check' to add python's dll to PATH
diff --git a/src/PythonQt.cpp b/src/PythonQt.cpp
index e5c4a93a6..b8fac6694 100644
--- a/src/PythonQt.cpp
+++ b/src/PythonQt.cpp
@@ -2643,6 +2643,24 @@ PythonQtClassInfo* PythonQtPrivate::getClassInfo( const QByteArray& className )
       }
     }
   }
+
+  if (!result) {
+	bool ambiguity = false;
+	for(auto &&key: _knownClassInfos.keys()) {
+		if (key.indexOf(QByteArray("::") + className) >= 0) {
+			if (!result) {
+				result = _knownClassInfos.value(key);
+			} else {
+				ambiguity = true;
+				std::cerr << "Multiple candidates found" << std::endl;
+			}
+		}
+	}
+	if (ambiguity) {
+		return nullptr;
+	}
+  }
+
   return result;
 }
 
diff --git a/src/src.pri b/src/src.pri
index 68f5bfb23..dbe3d43b7 100644
--- a/src/src.pri
+++ b/src/src.pri
@@ -2,7 +2,7 @@ DEFINES +=  PYTHONQT_EXPORTS
 
 INCLUDEPATH += $$PWD
 
-CONFIG += c++11
+CONFIG += c++11 c++17
 
 gcc:!no_warn:!clang:QMAKE_CXXFLAGS += -Wno-error=missing-field-initializers
 *-clang*:!no_warn:QMAKE_CXXFLAGS += -Wno-error=sometimes-uninitialized