diff --git a/stack-master.yaml b/stack-master.yaml
index 9a6b2c80..19f82205 100644
--- a/stack-master.yaml
+++ b/stack-master.yaml
@@ -1,7 +1,7 @@
 # This stack.yaml is used to build xmonad-contrib with master versions
 # of X11 and xmonad
 
-resolver: lts-17.14
+resolver: lts-18.14
 
 packages:
 - ./
diff --git a/stack.yaml b/stack.yaml
index d220f5f4..d4e0ead1 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,7 +1,7 @@
 # This stack.yaml is used to build xmonad-contrib with released versions
 # of X11 and xmonad
 
-resolver: lts-17.14
+resolver: lts-18.14
 
 packages:
 - ./