diff --git a/src/Model.hs b/src/Model.hs
index 54edc0b..5db7adc 100644
--- a/src/Model.hs
+++ b/src/Model.hs
@@ -6,6 +6,7 @@
 {-# LANGUAGE TemplateHaskell       #-}
 {-# LANGUAGE TypeFamilies          #-}
 {-# LANGUAGE UndecidableInstances  #-}
+{-# LANGUAGE DataKinds  #-}
 
 module Model where
 
diff --git a/stack.yaml b/stack.yaml
index ba07302..5af9d27 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-16.15
+resolver: lts-18.11
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.