diff --git a/CMakeLists.txt b/CMakeLists.txt
index 65448a1c..ed69a67a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -77,7 +77,11 @@ IF(Qt5Widgets_FOUND)
     MESSAGE(STATUS "Found Qt ${Qt5Widgets_VERSION_STRING}")
 ELSE()
     FIND_PACKAGE(Qt4 4.8.0 REQUIRED)
-    IF(Qt4_FOUND OR QT4_FOUND)
+    IF(QT4_FOUND)
+        # Old FindQt4.cmake modules used the same flag with different case
+        SET(Qt4_FOUND TRUE)
+    ENDIF()
+    IF(Qt4_FOUND)
         MESSAGE(STATUS "Found Qt ${QT_VERSION_MAJOR}.${QT_VERSION_MINOR}.${QT_VERSION_PATCH}")
     ELSE()
         MESSAGE(FATAL_ERROR "No Qt4 or Qt5 found!")