diff --git a/app/current-output.hs b/app/current-output.hs
index 6272f3e..151707b 100644
--- a/app/current-output.hs
+++ b/app/current-output.hs
@@ -22,7 +22,7 @@ module Main (main) where
 --    _NET_DESKTOP_VIEWPORT
 -- 3) Find the name of the xrandr output whose position matches that from (2)
 
-import           Data.Maybe               (catMaybes, maybe)
+import           Data.Maybe
 
 import           Graphics.X11.Types
 import           Graphics.X11.Xlib
diff --git a/stack.yaml b/stack.yaml
index f5b329d..8c1e1eb 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -17,7 +17,7 @@
 #
 # resolver: ./custom-snapshot.yaml
 # resolver: https://example.com/snapshots/2018-01-01.yaml
-resolver: lts-14.12
+resolver: lts-16.31
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.
@@ -64,3 +64,11 @@ packages:
 #
 # Allow a newer minor version of GHC than the snapshot specifies
 # compiler-check: newer-minor
+nix:
+  enable: true
+  packages:
+    - xorg.libX11
+    - xorg.libXrandr
+    - xorg.libXScrnSaver
+    - xorg.libXext
+    - zlib
diff --git a/stack.yaml.lock b/stack.yaml.lock
index a311fe3..c222190 100644
--- a/stack.yaml.lock
+++ b/stack.yaml.lock
@@ -6,7 +6,7 @@
 packages: []
 snapshots:
 - completed:
-    size: 545658
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/14/12.yaml
-    sha256: 26b807457213126d26b595439d705dc824dbb7618b0de6b900adc2bf6a059406
-  original: lts-14.12
+    size: 534126
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/16/31.yaml
+    sha256: 637fb77049b25560622a224845b7acfe81a09fdb6a96a3c75997a10b651667f6
+  original: lts-16.31