diff --git a/appveyor.yml b/appveyor.yml
index 32d49842..d0398226 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,6 +1,6 @@
 version: 1.0.10.{build}
 
-os: Visual Studio 2017
+os: Visual Studio 2015
 
 environment:
   matrix: