diff --git a/Stencil.podspec.json b/Stencil.podspec.json
index fceb79ce..d877c7a1 100644
--- a/Stencil.podspec.json
+++ b/Stencil.podspec.json
@@ -23,6 +23,7 @@
     "osx": "10.9",
     "tvos": "9.0"
   },
+  "swift_version": "4.1",
   "requires_arc": true,
   "dependencies": {
     "PathKit": [