diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## [0.5.0.5] - 2024-09-19
+
+### Added
+
+* `Validity v => Validity (IntMap v)`
+
 ## [0.5.0.4] - 2020-06-17
 
 ### Added
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2016-2020 Tom Sydney Kerckhove
+Copyright (c) 2016-2021 Tom Sydney Kerckhove
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/Setup.hs b/Setup.hs
deleted file mode 100644
--- a/Setup.hs
+++ /dev/null
@@ -1,3 +0,0 @@
-import Distribution.Simple
-
-main = defaultMain
diff --git a/src/Data/Validity/Containers.hs b/src/Data/Validity/Containers.hs
--- a/src/Data/Validity/Containers.hs
+++ b/src/Data/Validity/Containers.hs
@@ -3,12 +3,14 @@
 
 module Data.Validity.Containers
   ( module Data.Validity.Map,
+    module Data.Validity.IntMap,
     module Data.Validity.Sequence,
     module Data.Validity.Set,
     module Data.Validity.Tree,
   )
 where
 
+import Data.Validity.IntMap
 import Data.Validity.Map
 import Data.Validity.Sequence
 import Data.Validity.Set
diff --git a/src/Data/Validity/IntMap.hs b/src/Data/Validity/IntMap.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Validity/IntMap.hs
@@ -0,0 +1,22 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+
+module Data.Validity.IntMap
+  ( decorateIntMap,
+  )
+where
+
+import Data.IntMap (IntMap)
+import qualified Data.IntMap as IM
+import Data.Validity
+
+-- | A 'IntMap' of things is valid if all the keys and values are valid and the 'IntMap' itself
+-- is valid.
+instance (Validity v) => Validity (IntMap v) where
+  validate m =
+    decorate "IntMap elements" $
+      decorateIntMap m validate
+
+decorateIntMap :: IntMap v -> (v -> Validation) -> Validation
+decorateIntMap m func = IM.foldMapWithKey go m
+  where
+    go k v = decorate ("The key/value at key " ++ show k) $ func v
diff --git a/src/Data/Validity/Map.hs b/src/Data/Validity/Map.hs
--- a/src/Data/Validity/Map.hs
+++ b/src/Data/Validity/Map.hs
@@ -1,8 +1,9 @@
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 
 module Data.Validity.Map
-  ( decorateMap
-  ) where
+  ( decorateMap,
+  )
+where
 
 import Data.Map (Map)
 import qualified Data.Map as M
@@ -13,12 +14,13 @@
 instance (Show k, Ord k, Validity k, Validity v) => Validity (Map k v) where
   validate m =
     mconcat
-      [ declare "The Map structure is valid." $ M.valid m
-      , decorate "Map elements" $
-        decorateMap m $ \k v -> mconcat [delve "The key" k, delve "The value" v]
+      [ declare "The Map structure is valid." $ M.valid m,
+        decorate "Map elements" $
+          decorateMap m $
+            \k v -> mconcat [delve "The key" k, delve "The value" v]
       ]
 
-decorateMap :: Show k => Map k v -> (k -> v -> Validation) -> Validation
+decorateMap :: (Show k) => Map k v -> (k -> v -> Validation) -> Validation
 decorateMap m func = M.foldMapWithKey go m
   where
     go k v = decorate ("The key/value at key " ++ show k) $ func k v
diff --git a/src/Data/Validity/Sequence.hs b/src/Data/Validity/Sequence.hs
--- a/src/Data/Validity/Sequence.hs
+++ b/src/Data/Validity/Sequence.hs
@@ -2,11 +2,10 @@
 
 module Data.Validity.Sequence where
 
-import Data.Validity
-
 import Data.Foldable (toList)
 import Data.Sequence (Seq)
+import Data.Validity
 
 -- | A 'Seq'uence of things is valid if all the elements are valid.
-instance Validity v => Validity (Seq v) where
-    validate s = annotate (toList s) "Seq elements"
+instance (Validity v) => Validity (Seq v) where
+  validate s = annotate (toList s) "Seq elements"
diff --git a/src/Data/Validity/Set.hs b/src/Data/Validity/Set.hs
--- a/src/Data/Validity/Set.hs
+++ b/src/Data/Validity/Set.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 
 module Data.Validity.Set where
@@ -16,7 +15,6 @@
       [ declare "The set structure is valid." $ S.valid s,
         annotate (S.toList s) "Set elements"
       ]
-#if MIN_VERSION_containers(0,6,0)
-distinctOrd :: Ord a => [a] -> Bool
+
+distinctOrd :: (Ord a) => [a] -> Bool
 distinctOrd ls = nubOrd ls == ls
-#endif
diff --git a/src/Data/Validity/Tree.hs b/src/Data/Validity/Tree.hs
--- a/src/Data/Validity/Tree.hs
+++ b/src/Data/Validity/Tree.hs
@@ -2,11 +2,10 @@
 
 module Data.Validity.Tree where
 
-import Data.Validity
-
 import Data.Tree
+import Data.Validity
 
 -- | A 'Tree' of things is valid if all the things in the 'Tree' are valid.
-instance Validity a => Validity (Tree a) where
-    validate (Node rl sf) =
-        mconcat [annotate rl "rootLabel", annotate sf "subForest"]
+instance (Validity a) => Validity (Tree a) where
+  validate (Node rl sf) =
+    mconcat [annotate rl "rootLabel", annotate sf "subForest"]
diff --git a/validity-containers.cabal b/validity-containers.cabal
--- a/validity-containers.cabal
+++ b/validity-containers.cabal
@@ -1,20 +1,18 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.33.0.
+-- This file has been generated from package.yaml by hpack version 0.36.0.
 --
 -- see: https://github.com/sol/hpack
---
--- hash: 2e970343bc40866f2768fe78bd9427b658402d4bf787b23ad793a1cae658a82f
 
 name:           validity-containers
-version:        0.5.0.4
+version:        0.5.0.5
 synopsis:       Validity instances for containers
 category:       Validity
 homepage:       https://github.com/NorfairKing/validity#readme
 bug-reports:    https://github.com/NorfairKing/validity/issues
 author:         Tom Sydney Kerckhove
 maintainer:     syd@cs-syd.eu
-copyright:      Copyright: (c) 2016-2020 Tom Sydney Kerckhove
+copyright:      Copyright: (c) 2016-2021 Tom Sydney Kerckhove
 license:        MIT
 license-file:   LICENSE
 build-type:     Simple
@@ -28,6 +26,7 @@
 library
   exposed-modules:
       Data.Validity.Containers
+      Data.Validity.IntMap
       Data.Validity.Map
       Data.Validity.Sequence
       Data.Validity.Set