diff --git a/appveyor.yml b/appveyor.yml
index 90bf78f..3031319 100755
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -4,7 +4,7 @@ environment:
   matrix:
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       platform: x64
-      FLAGS: "/permissive- /utf-8 /Zc:__cplusplus"
+      FLAGS: "/std:c++14"
       GENERATOR: Visual Studio 14 2015
 
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017