diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,13 @@
+2.9
+---
+
+- Support `insert-ordered-containers` by adding compatibility layer (see [#262](https://github.com/GetShopTV/swagger2/pull/262)).
+- Relax upper bound for test dependencies (see [#259](https://github.com/GetShopTV/swagger2/pull/259)).
+
+2.8.11
+---
+
+- Add DayOfWeek instance for GHC >= 8.8.4 (see [#250](https://github.com/GetShopTV/swagger2/pull/250));
 2.8.10
 ---
 
diff --git a/src/Data/HashMap/Strict/InsOrd/Compat.hs b/src/Data/HashMap/Strict/InsOrd/Compat.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/HashMap/Strict/InsOrd/Compat.hs
@@ -0,0 +1,442 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE DeriveTraversable #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+-- |
+-- Module:      Data.HashMap.Strict.InsOrd.Compat
+-- Maintainer:  Nickolay Kudasov <nickolay@getshoptv.com>
+-- Stability:   experimental
+--
+-- Compatibility wrapper around @insert-ordered-containers@ to mitigate the
+-- breaking changes introduced in @insert-ordered-containers-0.3.0@:
+-- <https://github.com/erikd/insert-ordered-containers/pull/8>.
+--
+-- That change fixed 'Eq' and Aeson instances in the upstream package, but it is
+-- a behavioral break for @swagger2@ where we need stable Swagger Schema
+-- generation and JSON object-like encoding.
+--
+-- This module keeps the old @swagger2@ expectations:
+--
+-- * 'InsOrdHashMap' values are encoded as JSON objects (not arrays of key/value
+--   tuples), so field names remain first-class object keys.
+-- * Equality intentionally ignores insertion order (compares as plain hash
+--   maps), which matches how many tests currently assert JSON equality.
+--
+-- Simple encoding examples:
+--
+-- >>> import Data.Aeson (encode, eitherDecode)
+-- >>> import qualified Data.ByteString.Lazy.Char8 as BSL8
+-- >>> import qualified Data.HashMap.Strict as HM
+-- >>> import qualified Data.HashMap.Strict.InsOrd.Compat as IOHM
+-- >>> let decodeIOHM s = either error id (eitherDecode (BSL8.pack s) :: Either String (IOHM.InsOrdHashMap String Int))
+--
+-- A regular hash map has no insertion order guarantee:
+--
+-- >>> encode (HM.fromList [("a", 1 :: Int), ("b", 2)])
+-- "{\"a\":1,\"b\":2}"
+-- >>> encode (HM.fromList [("b", 1 :: Int), ("a", 2)])
+-- "{\"a\":2,\"b\":1}"
+--
+-- Our compat 'InsOrdHashMap' encodes to a JSON object as well, but preserves insertion order:
+--
+-- >>> encode (IOHM.fromList [("a", 1 :: Int), ("b", 2)])
+-- "{\"a\":1,\"b\":2}"
+-- >>> encode (IOHM.fromList [("b", 1 :: Int), ("a", 2)])
+-- "{\"b\":1,\"a\":2}"
+--
+-- Round-tripping through decode/encode demonstrates the caveat: encoding
+-- preserves insertion order, but decoded object key order is not guaranteed.
+--
+-- >>> encode (decodeIOHM "{\"a\":1,\"b\":2}")
+-- "{\"a\":1,\"b\":2}"
+-- >>> encode (decodeIOHM "{\"b\":1,\"a\":2}")
+-- "{\"a\":2,\"b\":1}"
+--
+-- This object encoding is what @swagger2@ wants for generated Swagger
+-- definitions/properties because it keeps emitted schemas easy to consume and
+-- stable in practice.
+--
+-- Important caveat: decoding cannot be fully stable with respect to insertion
+-- order due to @aeson@ limitations. In particular, object parsing goes through
+-- structures that do not preserve all ordering guarantees end-to-end. We accept
+-- this trade-off for now because the primary requirement is deterministic
+-- /encoding/ for generated Swagger Schema artifacts.
+--
+-- Many tests rely on @aesonQQ@-style JSON equality, where semantic object
+-- equality matters more than insertion order. Comparing via plain hash maps
+-- makes those tests robust under benign key-order variation. This is a weaker
+-- notion of equality and hopefully will be revisited later.
+module Data.HashMap.Strict.InsOrd.Compat (
+  InsOrdHashMap,
+  -- * Construction
+  empty,
+  singleton,
+  -- * Basic interface
+  null,
+  size,
+  member,
+  lookup,
+  lookupDefault,
+  insert,
+  insertWith,
+  delete,
+  adjust,
+  update,
+  alter,
+  -- * Combine
+  union,
+  unionWith,
+  unionWithKey,
+  unions,
+  -- * Transformations
+  map,
+  mapKeys,
+  traverseKeys,
+  mapWithKey,
+  traverseWithKey,
+  -- ** Unordered
+  unorderedTraverse,
+  unorderedTraverseWithKey,
+  -- * Difference and intersection
+  difference,
+  intersection,
+  intersectionWith,
+  intersectionWithKey,
+  -- * Folds
+  foldl',
+  foldlWithKey',
+  foldr,
+  foldrWithKey,
+  foldMapWithKey,
+  -- ** Unordered
+  unorderedFoldMap,
+  unorderedFoldMapWithKey,
+  -- * Filter
+  filter,
+  filterWithKey,
+  mapMaybe,
+  mapMaybeWithKey,
+  -- * Conversions
+  keys,
+  elems,
+  toList,
+  toRevList,
+  fromList,
+  toHashMap,
+  fromHashMap,
+  -- * Lenses
+  hashMap,
+  unorderedTraversal,
+  -- * Debugging
+  valid,
+  ) where
+
+#if !MIN_VERSION_insert_ordered_containers(0,3,0)
+import Data.HashMap.Strict.InsOrd
+#else
+import qualified Data.HashMap.Strict.InsOrd as InsOrdHashMap
+
+import Prelude hiding (null, size, member, lookup, lookupDefault, map, foldl', filter)
+import qualified Prelude
+
+import qualified Data.Aeson as A
+import qualified Data.Aeson.Encoding as E
+import           Data.HashMap.Strict (HashMap)
+import qualified Data.HashMap.Strict as HashMap
+
+import qualified GHC.Exts as Exts
+
+import Data.Data                       (Data)
+import Data.Foldable                   (Foldable (foldMap))
+import Data.Hashable                   (Hashable (..))
+
+import qualified Control.Lens        as Lens
+import Control.Lens
+       (At (..), Index, Iso, IxValue, Ixed (..), Traversal, _1, _2, iso, (<&>))
+
+import qualified Optics.Core         as Optics
+
+newtype InsOrdHashMap k v = InsOrdHashMap { unCompatInsOrdHashMap :: InsOrdHashMap.InsOrdHashMap k v }
+  deriving (Show, Read, Data, Functor, Foldable, Traversable, Semigroup, Monoid)
+
+instance (Eq k, Eq v) => Eq (InsOrdHashMap k v) where
+    a == b = toHashMap a == toHashMap b
+
+instance (Eq k, Hashable k) => Exts.IsList (InsOrdHashMap k v) where
+    type Item (InsOrdHashMap k v) = Exts.Item (InsOrdHashMap.InsOrdHashMap k v)
+    fromList = InsOrdHashMap . InsOrdHashMap.fromList
+    toList   = InsOrdHashMap.toList . unCompatInsOrdHashMap
+
+-------------------------------------------------------------------------------
+-- Aeson
+-------------------------------------------------------------------------------
+
+instance (A.ToJSONKey k) => A.ToJSON1 (InsOrdHashMap k) where
+    liftToJSON _ t _ = case A.toJSONKey :: A.ToJSONKeyFunction k of
+      A.ToJSONKeyText f _ -> A.object . fmap (\(k, v) -> (f k, t v)) . toList
+      A.ToJSONKeyValue f _ -> A.toJSON . fmap (\(k,v) -> A.toJSON (f k, t v)) . toList
+
+    liftToEncoding o t _ = case A.toJSONKey :: A.ToJSONKeyFunction k of
+      A.ToJSONKeyText _ f ->  E.dict f t foldrWithKey
+      A.ToJSONKeyValue _ f -> E.list (A.liftToEncoding2 (const False) f (E.list f) o t (E.list t)) . toList
+
+instance (A.ToJSONKey k, A.ToJSON v) => A.ToJSON (InsOrdHashMap k v) where
+    toJSON = A.toJSON1
+    toEncoding = A.toEncoding1
+
+-------------------------------------------------------------------------------
+
+instance (Eq k, Hashable k, A.FromJSONKey k) => A.FromJSON1 (InsOrdHashMap k) where
+    liftParseJSON o p pl v = fromList . HashMap.toList <$> A.liftParseJSON o p pl v
+
+instance (Eq k, Hashable k, A.FromJSONKey k, A.FromJSON v) => A.FromJSON (InsOrdHashMap k v) where
+    parseJSON = A.parseJSON1
+
+-------------------------------------------------------------------------------
+-- indexed-traversals
+-------------------------------------------------------------------------------
+
+instance (Eq k, Hashable k) => Optics.FunctorWithIndex k (InsOrdHashMap k) where
+    imap = mapWithKey
+instance (Eq k, Hashable k) => Optics.FoldableWithIndex k (InsOrdHashMap k) where
+    ifoldMap = foldMapWithKey
+    ifoldr   = foldrWithKey
+instance (Eq k, Hashable k) => Optics.TraversableWithIndex k (InsOrdHashMap k) where
+    itraverse = traverseWithKey
+
+-------------------------------------------------------------------------------
+-- Lens
+-------------------------------------------------------------------------------
+
+type instance Index (InsOrdHashMap k v) = k
+type instance IxValue (InsOrdHashMap k v) = v
+
+instance (Eq k, Hashable k) => Ixed (InsOrdHashMap k v) where
+    ix k f m = ixImpl k pure f m
+    {-# INLINABLE ix #-}
+
+ixImpl
+  :: (Eq k, Hashable k, Functor f)
+  => k
+  -> (InsOrdHashMap k v -> f (InsOrdHashMap k v))
+  -> (v -> f v)
+  -> InsOrdHashMap k v
+  -> f (InsOrdHashMap k v)
+ixImpl k point f m = case lookup k m of
+    Just v  -> f v <&> \v' -> insert k v' m
+    Nothing -> point m
+{-# INLINE ixImpl #-}
+
+instance (Eq k, Hashable k) => At (InsOrdHashMap k a) where
+    at k f m = f mv <&> \r -> case r of
+        Nothing -> maybe m (const (delete k m)) mv
+        Just v' -> insert k v' m
+      where mv = lookup k m
+    {-# INLINABLE at #-}
+
+-------------------------------------------------------------------------------
+-- Optics
+-------------------------------------------------------------------------------
+
+type instance Optics.Index (InsOrdHashMap k v) = k
+type instance Optics.IxValue (InsOrdHashMap k v) = v
+
+instance (Eq k, Hashable k) => Optics.Ixed (InsOrdHashMap k v) where
+    ix k = Optics.atraversalVL $ \point f m -> ixImpl k point f m
+    {-# INLINE ix #-}
+
+instance (Eq k, Hashable k) => Optics.At (InsOrdHashMap k a) where
+    at k = Optics.lensVL $ \f m -> Lens.at k f m
+    {-# INLINE at #-}
+
+-------------------------------------------------------------------------------
+
+-- | This is a slight lie, as roundtrip doesn't preserve ordering.
+hashMap :: Iso (InsOrdHashMap k a) (InsOrdHashMap k b) (HashMap k a) (HashMap k b)
+hashMap = iso toHashMap fromHashMap
+
+unorderedTraversal :: Traversal (InsOrdHashMap k a) (InsOrdHashMap k b) a b
+unorderedTraversal = hashMap . traverse
+
+-------------------------------------------------------------------------------
+-- * Construction
+-------------------------------------------------------------------------------
+
+empty :: InsOrdHashMap k v
+empty = InsOrdHashMap InsOrdHashMap.empty
+
+singleton :: Hashable k => k -> v -> InsOrdHashMap k v
+singleton k v = InsOrdHashMap (InsOrdHashMap.singleton k v)
+
+-------------------------------------------------------------------------------
+-- * Basic interface
+-------------------------------------------------------------------------------
+
+null :: InsOrdHashMap k v -> Bool
+null = InsOrdHashMap.null . unCompatInsOrdHashMap
+
+size :: InsOrdHashMap k v -> Int
+size = InsOrdHashMap.size . unCompatInsOrdHashMap
+
+insert :: Hashable k => k -> v -> InsOrdHashMap k v -> InsOrdHashMap k v
+insert k v = InsOrdHashMap . InsOrdHashMap.insert k v . unCompatInsOrdHashMap
+
+insertWith :: Hashable k => (v -> v -> v) -> k -> v -> InsOrdHashMap k v -> InsOrdHashMap k v
+insertWith f k v = InsOrdHashMap . InsOrdHashMap.insertWith f k v . unCompatInsOrdHashMap
+
+delete :: Hashable k => k -> InsOrdHashMap k v -> InsOrdHashMap k v
+delete k = InsOrdHashMap . InsOrdHashMap.delete k . unCompatInsOrdHashMap
+
+adjust :: Hashable k => (v -> v) -> k -> InsOrdHashMap k v -> InsOrdHashMap k v
+adjust f k = InsOrdHashMap . InsOrdHashMap.adjust f k . unCompatInsOrdHashMap
+
+update :: Hashable k => (v -> Maybe v) -> k -> InsOrdHashMap k v -> InsOrdHashMap k v
+update f k = InsOrdHashMap . InsOrdHashMap.update f k . unCompatInsOrdHashMap
+
+alter :: Hashable k => (Maybe v -> Maybe v) -> k -> InsOrdHashMap k v -> InsOrdHashMap k v
+alter f k = InsOrdHashMap . InsOrdHashMap.alter f k . unCompatInsOrdHashMap
+
+member :: Hashable k => k -> InsOrdHashMap k v -> Bool
+member k = InsOrdHashMap.member k . unCompatInsOrdHashMap
+
+lookup :: Hashable k => k -> InsOrdHashMap k v -> Maybe v
+lookup k = InsOrdHashMap.lookup k . unCompatInsOrdHashMap
+
+lookupDefault :: Hashable k => v -> k -> InsOrdHashMap k v -> v
+lookupDefault k def = InsOrdHashMap.lookupDefault k def . unCompatInsOrdHashMap
+
+-- * Combine
+
+union :: Hashable k => InsOrdHashMap k v -> InsOrdHashMap k v -> InsOrdHashMap k v
+union m1 m2 = InsOrdHashMap (InsOrdHashMap.union (unCompatInsOrdHashMap m1) (unCompatInsOrdHashMap m2))
+
+unionWith :: Hashable k => (v -> v -> v) -> InsOrdHashMap k v -> InsOrdHashMap k v -> InsOrdHashMap k v
+unionWith f m1 m2 = InsOrdHashMap (InsOrdHashMap.unionWith f (unCompatInsOrdHashMap m1) (unCompatInsOrdHashMap m2))
+
+unionWithKey :: Hashable k => (k -> v -> v -> v) -> InsOrdHashMap k v -> InsOrdHashMap k v -> InsOrdHashMap k v
+unionWithKey f m1 m2 = InsOrdHashMap (InsOrdHashMap.unionWithKey f (unCompatInsOrdHashMap m1) (unCompatInsOrdHashMap m2))
+
+unions :: Hashable k => [InsOrdHashMap k v] -> InsOrdHashMap k v
+unions = InsOrdHashMap . InsOrdHashMap.unions . Prelude.map unCompatInsOrdHashMap
+
+-------------------------------------------------------------------------------
+-- * Transformations
+-------------------------------------------------------------------------------
+
+map :: (v -> v) -> InsOrdHashMap k v -> InsOrdHashMap k v
+map f = InsOrdHashMap . InsOrdHashMap.map f . unCompatInsOrdHashMap
+
+mapKeys :: Hashable k => (k -> k) -> InsOrdHashMap k v -> InsOrdHashMap k v
+mapKeys f = InsOrdHashMap . InsOrdHashMap.mapKeys f . unCompatInsOrdHashMap
+
+traverseKeys :: (Applicative f, Hashable k) => (k -> f k) -> InsOrdHashMap k v -> f (InsOrdHashMap k v)
+traverseKeys f = fmap InsOrdHashMap . InsOrdHashMap.traverseKeys f . unCompatInsOrdHashMap
+
+mapWithKey :: (k -> v1 -> v2) -> InsOrdHashMap k v1 -> InsOrdHashMap k v2
+mapWithKey f = InsOrdHashMap . InsOrdHashMap.mapWithKey f . unCompatInsOrdHashMap
+
+traverseWithKey :: (Applicative f, Hashable k) => (k -> v1 -> f v2) -> InsOrdHashMap k v1 -> f (InsOrdHashMap k v2)
+traverseWithKey f = fmap InsOrdHashMap . InsOrdHashMap.traverseWithKey f . unCompatInsOrdHashMap
+
+-- ** Unordered
+
+unorderedTraverse :: (Applicative f, Hashable k) => (v -> f v) -> InsOrdHashMap k v -> f (InsOrdHashMap k v)
+unorderedTraverse f = fmap InsOrdHashMap . InsOrdHashMap.unorderedTraverse f . unCompatInsOrdHashMap
+
+unorderedTraverseWithKey :: (Applicative f, Hashable k) => (k -> v -> f v) -> InsOrdHashMap k v -> f (InsOrdHashMap k v)
+unorderedTraverseWithKey f = fmap InsOrdHashMap . InsOrdHashMap.unorderedTraverseWithKey f . unCompatInsOrdHashMap
+
+-------------------------------------------------------------------------------
+-- * Difference and intersection
+-------------------------------------------------------------------------------
+
+difference :: Hashable k => InsOrdHashMap k v -> InsOrdHashMap k v -> InsOrdHashMap k v
+difference m1 m2 = InsOrdHashMap (InsOrdHashMap.difference (unCompatInsOrdHashMap m1) (unCompatInsOrdHashMap m2))
+
+intersection :: Hashable k => InsOrdHashMap k v -> InsOrdHashMap k v -> InsOrdHashMap k v
+intersection m1 m2 = InsOrdHashMap (InsOrdHashMap.intersection (unCompatInsOrdHashMap m1) (unCompatInsOrdHashMap m2))
+
+intersectionWith :: Hashable k => (v -> v -> v) -> InsOrdHashMap k v -> InsOrdHashMap k v -> InsOrdHashMap k v
+intersectionWith f m1 m2 = InsOrdHashMap (InsOrdHashMap.intersectionWith f (unCompatInsOrdHashMap m1) (unCompatInsOrdHashMap m2))
+
+intersectionWithKey :: Hashable k => (k -> v -> v -> v) -> InsOrdHashMap k v -> InsOrdHashMap k v -> InsOrdHashMap k v
+intersectionWithKey f m1 m2 = InsOrdHashMap (InsOrdHashMap.intersectionWithKey f (unCompatInsOrdHashMap m1) (unCompatInsOrdHashMap m2))
+
+-------------------------------------------------------------------------------
+-- * Folds
+-------------------------------------------------------------------------------
+
+foldl' :: (a -> v -> a) -> a -> InsOrdHashMap k v -> a
+foldl' f z = InsOrdHashMap.foldl' f z . unCompatInsOrdHashMap
+
+foldlWithKey' :: (a -> k -> v -> a) -> a -> InsOrdHashMap k v -> a
+foldlWithKey' f z = InsOrdHashMap.foldlWithKey' f z . unCompatInsOrdHashMap
+
+foldMapWithKey :: Monoid m => (k -> v -> m) -> InsOrdHashMap k v -> m
+foldMapWithKey f = InsOrdHashMap.foldMapWithKey f . unCompatInsOrdHashMap
+
+foldrWithKey :: (k -> v -> a -> a) -> a -> InsOrdHashMap k v -> a
+foldrWithKey f z = InsOrdHashMap.foldrWithKey f z . unCompatInsOrdHashMap
+
+-- ** Unordered
+
+unorderedFoldMap :: Monoid m => (v -> m) -> InsOrdHashMap k v -> m
+unorderedFoldMap f = InsOrdHashMap.unorderedFoldMap f . unCompatInsOrdHashMap
+
+unorderedFoldMapWithKey :: Monoid m => (k -> v -> m) -> InsOrdHashMap k v -> m
+unorderedFoldMapWithKey f = InsOrdHashMap.unorderedFoldMapWithKey f . unCompatInsOrdHashMap
+
+-------------------------------------------------------------------------------
+-- * Filter
+-------------------------------------------------------------------------------
+
+filter :: (v -> Bool) -> InsOrdHashMap k v -> InsOrdHashMap k v
+filter f = InsOrdHashMap . InsOrdHashMap.filter f . unCompatInsOrdHashMap
+
+filterWithKey :: (k -> v -> Bool) -> InsOrdHashMap k v -> InsOrdHashMap k v
+filterWithKey f = InsOrdHashMap . InsOrdHashMap.filterWithKey f . unCompatInsOrdHashMap
+
+mapMaybe :: (v -> Maybe v) -> InsOrdHashMap k v -> InsOrdHashMap k v
+mapMaybe f = InsOrdHashMap . InsOrdHashMap.mapMaybe f . unCompatInsOrdHashMap
+
+mapMaybeWithKey :: (k -> v -> Maybe v) -> InsOrdHashMap k v -> InsOrdHashMap k v
+mapMaybeWithKey f = InsOrdHashMap . InsOrdHashMap.mapMaybeWithKey f . unCompatInsOrdHashMap
+
+-------------------------------------------------------------------------------
+-- * Conversions
+-------------------------------------------------------------------------------
+
+keys :: InsOrdHashMap k v -> [k]
+keys = InsOrdHashMap.keys . unCompatInsOrdHashMap
+
+elems :: InsOrdHashMap k v -> [v]
+elems = InsOrdHashMap.elems . unCompatInsOrdHashMap
+
+toRevList :: InsOrdHashMap k v -> [(k, v)]
+toRevList = InsOrdHashMap.toRevList . unCompatInsOrdHashMap
+
+fromList :: Hashable k => [(k, v)] -> InsOrdHashMap k v
+fromList = InsOrdHashMap . InsOrdHashMap.fromList
+
+toList :: InsOrdHashMap k v -> [(k, v)]
+toList = InsOrdHashMap.toList . unCompatInsOrdHashMap
+
+toHashMap :: InsOrdHashMap k v -> HashMap k v
+toHashMap = InsOrdHashMap.toHashMap . unCompatInsOrdHashMap
+
+fromHashMap :: HashMap k v -> InsOrdHashMap k v
+fromHashMap = InsOrdHashMap . InsOrdHashMap.fromHashMap
+
+-------------------------------------------------------------------------------
+-- * Debugging
+-------------------------------------------------------------------------------
+
+valid :: (Eq k, Hashable k) => InsOrdHashMap k v -> Bool
+valid = InsOrdHashMap.valid . unCompatInsOrdHashMap
+
+#endif
diff --git a/src/Data/Swagger.hs b/src/Data/Swagger.hs
--- a/src/Data/Swagger.hs
+++ b/src/Data/Swagger.hs
@@ -124,7 +124,7 @@
 -- $setup
 -- >>> import Control.Lens
 -- >>> import Data.Aeson
--- >>> import qualified Data.HashMap.Strict.InsOrd as IOHM
+-- >>> import qualified Data.HashMap.Strict.InsOrd.Compat as IOHM
 -- >>> import Data.Monoid
 -- >>> import Data.Proxy
 -- >>> import GHC.Generics
diff --git a/src/Data/Swagger/Internal.hs b/src/Data/Swagger/Internal.hs
--- a/src/Data/Swagger/Internal.hs
+++ b/src/Data/Swagger/Internal.hs
@@ -44,8 +44,8 @@
 import           Network.HTTP.Media       (MediaType)
 import           Text.Read                (readMaybe)
 
-import           Data.HashMap.Strict.InsOrd (InsOrdHashMap)
-import qualified Data.HashMap.Strict.InsOrd as InsOrdHashMap
+import           Data.HashMap.Strict.InsOrd.Compat (InsOrdHashMap)
+import qualified Data.HashMap.Strict.InsOrd.Compat as InsOrdHashMap
 import qualified Data.Aeson.Key             as K
 import qualified Data.Aeson.KeyMap          as KM
 
diff --git a/src/Data/Swagger/Internal/AesonUtils.hs b/src/Data/Swagger/Internal/AesonUtils.hs
--- a/src/Data/Swagger/Internal/AesonUtils.hs
+++ b/src/Data/Swagger/Internal/AesonUtils.hs
@@ -45,7 +45,7 @@
 import qualified Data.Text as T
 import qualified Data.HashMap.Strict as HM
 import qualified Data.Set as Set
-import qualified Data.HashMap.Strict.InsOrd as InsOrd
+import qualified Data.HashMap.Strict.InsOrd.Compat as InsOrd
 import qualified Data.HashSet.InsOrd as InsOrdHS
 
 -------------------------------------------------------------------------------
diff --git a/src/Data/Swagger/Internal/Schema.hs b/src/Data/Swagger/Internal/Schema.hs
--- a/src/Data/Swagger/Internal/Schema.hs
+++ b/src/Data/Swagger/Internal/Schema.hs
@@ -36,7 +36,7 @@
 import qualified Data.HashMap.Strict as HashMap
 import           "unordered-containers" Data.HashSet (HashSet)
 import qualified "unordered-containers" Data.HashSet as HashSet
-import qualified Data.HashMap.Strict.InsOrd as InsOrdHashMap
+import qualified Data.HashMap.Strict.InsOrd.Compat as InsOrdHashMap
 import Data.Int
 import Data.IntSet (IntSet)
 import Data.IntMap (IntMap)
@@ -74,6 +74,9 @@
 import GHC.TypeLits (TypeError, ErrorMessage(..))
 import qualified Data.Aeson.KeyMap as KM
 import Data.Aeson.Key (toText)
+#if ( __GLASGOW_HASKELL__ > 884 )
+import Data.Time (DayOfWeek(Monday, Sunday))
+#endif
 
 unnamed :: Schema -> NamedSchema
 unnamed schema = NamedSchema Nothing schema
@@ -144,10 +147,6 @@
     Proxy a -> Declare (Definitions Schema) NamedSchema
   declareNamedSchema = genericDeclareNamedSchema defaultSchemaOptions
 
-instance ToSchema TimeOfDay where
-  declareNamedSchema _ = pure $ named "TimeOfDay" $ timeSchema "hh:MM:ss"
-    & example ?~ toJSON (TimeOfDay 12 33 15)
-
 -- | Convert a type into a schema and declare all used schema definitions.
 declareSchema :: ToSchema a => Proxy a -> Declare (Definitions Schema) Schema
 declareSchema = fmap _namedSchemaSchema . declareNamedSchema
@@ -496,6 +495,18 @@
 instance ToSchema ZonedTime where
   declareNamedSchema _ = pure $ named "ZonedTime" $ timeSchema "date-time"
     & example ?~ toJSON (ZonedTime (LocalTime (fromGregorian 2016 7 22) (TimeOfDay 7 40 0)) (hoursToTimeZone 3))
+
+instance ToSchema TimeOfDay where
+  declareNamedSchema _ = pure $ named "TimeOfDay" $ timeSchema "hh:MM:ss"
+    & example ?~ toJSON (TimeOfDay 12 33 15)
+
+#if ( __GLASGOW_HASKELL__ > 884 )
+instance ToSchema DayOfWeek where
+  declareNamedSchema _ = pure $ named "DayOfWeek" $ 
+    mempty
+    & type_ ?~ SwaggerString
+    & enum_ ?~ map toJSON [Monday .. Sunday]
+#endif
 
 instance ToSchema NominalDiffTime where
   declareNamedSchema _ = declareNamedSchema (Proxy :: Proxy Pico)
diff --git a/src/Data/Swagger/Internal/Schema/Validation.hs b/src/Data/Swagger/Internal/Schema/Validation.hs
--- a/src/Data/Swagger/Internal/Schema/Validation.hs
+++ b/src/Data/Swagger/Internal/Schema/Validation.hs
@@ -35,7 +35,7 @@
                                                       traverse_)
 import           Data.HashMap.Strict                 (HashMap)
 import qualified Data.HashMap.Strict                 as HashMap
-import qualified Data.HashMap.Strict.InsOrd          as InsOrdHashMap
+import qualified Data.HashMap.Strict.InsOrd.Compat   as InsOrdHashMap
 import qualified "unordered-containers" Data.HashSet as HashSet
 import           Data.Proxy
 import           Data.Scientific                     (Scientific, isInteger)
diff --git a/src/Data/Swagger/Internal/Utils.hs b/src/Data/Swagger/Internal/Utils.hs
--- a/src/Data/Swagger/Internal/Utils.hs
+++ b/src/Data/Swagger/Internal/Utils.hs
@@ -18,8 +18,8 @@
 import Data.Hashable (Hashable)
 import Data.HashMap.Strict (HashMap)
 import qualified Data.HashMap.Strict as HashMap
-import Data.HashMap.Strict.InsOrd (InsOrdHashMap)
-import qualified Data.HashMap.Strict.InsOrd as InsOrdHashMap
+import Data.HashMap.Strict.InsOrd.Compat (InsOrdHashMap)
+import qualified Data.HashMap.Strict.InsOrd.Compat as InsOrdHashMap
 import Data.Map (Map)
 import Data.Set (Set)
 import Data.Text (Text)
diff --git a/src/Data/Swagger/Operation.hs b/src/Data/Swagger/Operation.hs
--- a/src/Data/Swagger/Operation.hs
+++ b/src/Data/Swagger/Operation.hs
@@ -51,13 +51,13 @@
 import Data.Swagger.Lens
 import Data.Swagger.Schema
 
-import qualified Data.HashMap.Strict.InsOrd as InsOrdHashMap
-import Data.HashMap.Strict.InsOrd (InsOrdHashMap)
+import qualified Data.HashMap.Strict.InsOrd.Compat as InsOrdHashMap
+import Data.HashMap.Strict.InsOrd.Compat (InsOrdHashMap)
 import qualified Data.HashSet.InsOrd as InsOrdHS
 
 -- $setup
 -- >>> import Data.Aeson
--- >>> import qualified Data.HashMap.Strict.InsOrd as IOHM
+-- >>> import qualified Data.HashMap.Strict.InsOrd.Compat as IOHM
 -- >>> import Data.Proxy
 -- >>> import Data.Time
 
diff --git a/src/Data/Swagger/Optics.hs b/src/Data/Swagger/Optics.hs
--- a/src/Data/Swagger/Optics.hs
+++ b/src/Data/Swagger/Optics.hs
@@ -15,7 +15,7 @@
 -- library.
 --
 -- >>> import Data.Aeson
--- >>> import qualified Data.HashMap.Strict.InsOrd as IOHM
+-- >>> import qualified Data.HashMap.Strict.InsOrd.Compat as IOHM
 -- >>> import Optics.Core
 -- >>> :set -XOverloadedLabels
 --
diff --git a/src/Data/Swagger/Schema/Generator.hs b/src/Data/Swagger/Schema/Generator.hs
--- a/src/Data/Swagger/Schema/Generator.hs
+++ b/src/Data/Swagger/Schema/Generator.hs
@@ -12,7 +12,7 @@
 import           Data.Aeson
 import qualified Data.Aeson.KeyMap                       as KM
 import           Data.Aeson.Types
-import qualified Data.HashMap.Strict.InsOrd              as M
+import qualified Data.HashMap.Strict.InsOrd.Compat       as M
 import           Data.Maybe
 import           Data.Proxy
 import           Data.Scientific
diff --git a/swagger2.cabal b/swagger2.cabal
--- a/swagger2.cabal
+++ b/swagger2.cabal
@@ -1,6 +1,6 @@
 cabal-version:       >=1.10
 name:                swagger2
-version:             2.8.10
+version:             2.9
 
 synopsis:            Swagger 2.0 data model
 category:            Web, Swagger
@@ -41,6 +41,7 @@
 library
   hs-source-dirs:      src
   exposed-modules:
+    Data.HashMap.Strict.InsOrd.Compat
     Data.Swagger
     Data.Swagger.Declare
     Data.Swagger.Lens
@@ -84,7 +85,7 @@
     , generics-sop              >=0.5.1.0  && <0.6
     , hashable                  >=1.2.7.0  && <1.6
     , http-media                >=0.8.0.0  && <0.9
-    , insert-ordered-containers >=0.2.3    && <0.3
+    , insert-ordered-containers >=0.2.3    && <0.4
     , lens                      >=4.16.1   && <5.4
     , network                   >=2.6.3.5  && <3.3
     , optics-core               >=0.2      && <0.5
@@ -93,7 +94,7 @@
     , unordered-containers      >=0.2.9.0  && <0.3
     , uuid-types                >=1.0.3    && <1.1
     , vector                    >=0.12.0.1 && <0.14
-    , QuickCheck                >=2.10.1   && <2.16
+    , QuickCheck                >=2.10.1   && <2.17
 
   default-language:    Haskell2010
 
@@ -126,12 +127,12 @@
   build-depends:
       hspec                >=2.5.5   && <2.12
     , HUnit                >=1.6.0.0 && <1.7
-    , quickcheck-instances >=0.3.19  && <0.14
+    , quickcheck-instances >=0.3.19  && <0.4
     , utf8-string          >=1.0.1.1 && <1.1
 
   -- https://github.com/haskell/cabal/issues/3708
   build-tool-depends:
-    hspec-discover:hspec-discover >=2.5.5 && <2.9
+    hspec-discover:hspec-discover >=2.5.5 && <2.12
 
   other-modules:
     SpecCommon
diff --git a/test/Data/Swagger/SchemaSpec.hs b/test/Data/Swagger/SchemaSpec.hs
--- a/test/Data/Swagger/SchemaSpec.hs
+++ b/test/Data/Swagger/SchemaSpec.hs
@@ -9,7 +9,7 @@
 
 import Control.Lens ((^.))
 import Data.Aeson (Value)
-import qualified Data.HashMap.Strict.InsOrd as InsOrdHashMap
+import qualified Data.HashMap.Strict.InsOrd.Compat as InsOrdHashMap
 import Data.Proxy
 import Data.Set (Set)
 import qualified Data.Text as Text
diff --git a/test/Data/SwaggerSpec.hs b/test/Data/SwaggerSpec.hs
--- a/test/Data/SwaggerSpec.hs
+++ b/test/Data/SwaggerSpec.hs
@@ -12,7 +12,7 @@
 import Data.Aeson
 import Data.Aeson.QQ.Simple
 import Data.HashMap.Strict (HashMap)
-import qualified Data.HashMap.Strict.InsOrd as InsOrdHashMap
+import qualified Data.HashMap.Strict.InsOrd.Compat as InsOrdHashMap
 import qualified Data.HashSet.InsOrd as InsOrdHS
 import Data.Text (Text)