diff --git a/CHANGES.md b/CHANGES.md
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,6 +1,10 @@
 Unreleased
 =====
 
+* Replaced `mapAutoFilterValue` in `IsAutoFilter` typeclass with `Functor` superclass.
+* Exposed `MkSomeFilter` constraint.
+* Added support for building the project with `servant` version >= 0.19.
+
 0.3
 ===
 
diff --git a/servant-util.cabal b/servant-util.cabal
--- a/servant-util.cabal
+++ b/servant-util.cabal
@@ -1,13 +1,11 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.34.6.
+-- This file has been generated from package.yaml by hpack version 0.34.4.
 --
 -- see: https://github.com/sol/hpack
---
--- hash: f0ae0577e7cde4002a074bd5fada6d918ea3dc45baee134d38fa8e002ad66d9f
 
 name:           servant-util
-version:        0.3
+version:        0.4
 synopsis:       Servant servers utilities.
 description:    Basement for common Servant combinators like filtering, sorting, pagination and semantical logging.
 category:       Servant, Web
@@ -111,6 +109,7 @@
       QuickCheck
     , aeson
     , base >=4.7 && <5
+    , bytestring
     , constraints
     , containers
     , data-default
@@ -187,6 +186,7 @@
       QuickCheck
     , aeson
     , base >=4.7 && <5
+    , bytestring
     , constraints
     , containers
     , data-default
@@ -275,6 +275,7 @@
       QuickCheck
     , aeson
     , base >=4.7 && <5
+    , bytestring
     , constraints
     , containers
     , data-default
diff --git a/src/Servant/Util/Combinators/Filtering/Base.hs b/src/Servant/Util/Combinators/Filtering/Base.hs
--- a/src/Servant/Util/Combinators/Filtering/Base.hs
+++ b/src/Servant/Util/Combinators/Filtering/Base.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP           #-}
 {-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE TypeInType    #-}
 
@@ -20,8 +21,10 @@
     , AreAutoFilters (..)
     , FilteringValueParser (..)
     , OpsDescriptions
+    , EncodedQueryParam
     , parseFilteringValueAsIs
     , unsupportedFilteringValue
+    , encodeQueryParam
     , autoFiltersParsers
 
     , FilteringParamTypesOf
@@ -37,6 +40,10 @@
 import GHC.Exts (IsList)
 import Servant (FromHttpApiData (..), ToHttpApiData (..))
 import Servant.API (NoContent)
+#if MIN_VERSION_servant(0,19,0)
+import Data.ByteString.Builder (toLazyByteString)
+import qualified Data.ByteString.Lazy as BL
+#endif
 
 import Servant.Util.Common
 
@@ -90,13 +97,25 @@
 -- This is not a 'Map' to prevent developer-defined entries order.
 type OpsDescriptions = [(Text, Text)]
 
+-- | Specify the encoding type and function for query parameters.
+-- It's required due to this https://github.com/haskell-servant/servant/pull/1432
+#if MIN_VERSION_servant(0,19,0)
+type EncodedQueryParam = ByteString
+encodeQueryParam :: ToHttpApiData a => a  -> EncodedQueryParam
+encodeQueryParam = BL.toStrict . toLazyByteString . toEncodedUrlPiece
+#else
+type EncodedQueryParam = Text
+encodeQueryParam :: ToHttpApiData a => a  -> EncodedQueryParam
+encodeQueryParam = toQueryParam
+#endif
+
 -- | How auto filters appear in logging.
 class BuildableAutoFilter (filter :: Type -> Type) where
     buildAutoFilter
         :: Buildable a => Text -> filter a -> Builder
 
 -- | Application of a filter type to Servant API.
-class (Typeable filter, BuildableAutoFilter filter) =>
+class (Typeable filter, Functor filter, BuildableAutoFilter filter) =>
       IsAutoFilter (filter :: Type -> Type) where
 
     -- | For each supported filtering operation specifies a short plain-english
@@ -112,13 +131,7 @@
     -- | Encode a filter to query parameter value.
     autoFilterEncode
         :: ToHttpApiData a
-        => filter a -> (Text, Text)
-
-    mapAutoFilterValue
-        :: (a -> b) -> filter a -> filter b
-    default mapAutoFilterValue
-        :: Functor filter => (a -> b) -> filter a -> filter b
-    mapAutoFilterValue = fmap
+        => filter a -> (Text, EncodedQueryParam)
 
 -- | Multi-version of 'IsFilter'.
 class AreAutoFilters (filters :: [Type -> Type]) where
@@ -152,7 +165,7 @@
     forall filter. IsAutoFilter filter => SomeTypeAutoFilter (filter a)
 
 instance Functor SomeTypeAutoFilter where
-    fmap f (SomeTypeAutoFilter filtr) = SomeTypeAutoFilter (mapAutoFilterValue f filtr)
+    fmap f (SomeTypeAutoFilter filtr) = SomeTypeAutoFilter (fmap f filtr)
 
 instance Buildable a => Buildable (Text, SomeTypeAutoFilter a) where
     build (name, SomeTypeAutoFilter f) = buildAutoFilter name f
diff --git a/src/Servant/Util/Combinators/Filtering/Client.hs b/src/Servant/Util/Combinators/Filtering/Client.hs
--- a/src/Servant/Util/Combinators/Filtering/Client.hs
+++ b/src/Servant/Util/Combinators/Filtering/Client.hs
@@ -6,7 +6,7 @@
 
 import Data.Typeable (cast)
 import GHC.TypeLits (KnownSymbol)
-import Servant (ToHttpApiData (..), toQueryParam, (:>))
+import Servant (ToHttpApiData (..), (:>))
 import Servant.Client (HasClient (..))
 import Servant.Client.Core.Request (Request, appendToQueryString)
 
@@ -19,10 +19,10 @@
 -------------------------------------------------------------------------
 
 -- | For given filter return operation name and encoded value.
-typeFilterToReq :: ToHttpApiData a => TypeFilter fk a -> (Text, Text)
+typeFilterToReq :: ToHttpApiData a => TypeFilter fk a -> (Text, EncodedQueryParam)
 typeFilterToReq = \case
     TypeAutoFilter (SomeTypeAutoFilter filter) -> autoFilterEncode filter
-    TypeManualFilter val                       -> (DefFilteringCmd, toQueryParam val)
+    TypeManualFilter val                       -> (DefFilteringCmd, encodeQueryParam val)
 
 -- | Apply filter to a client request being built.
 class SomeFilterToReq params where
diff --git a/src/Servant/Util/Combinators/Filtering/Construction.hs b/src/Servant/Util/Combinators/Filtering/Construction.hs
--- a/src/Servant/Util/Combinators/Filtering/Construction.hs
+++ b/src/Servant/Util/Combinators/Filtering/Construction.hs
@@ -7,6 +7,8 @@
 module Servant.Util.Combinators.Filtering.Construction
     ( noFilters
     , mkFilteringSpec
+
+    , MkSomeFilter
     , (?/)
     , (?/=)
     , (?/<)
@@ -90,33 +92,39 @@
     mkTypeFilter = TypeManualFilter
 
 -- | Safely construct 'SomeFilter'.
-class MkSomeFilter name filter (origParams :: [TyNamedFilter]) (params :: [TyNamedFilter]) where
+class MkSomeFilter' name filter (origParams :: [TyNamedFilter]) (params :: [TyNamedFilter]) where
     mkSomeFilter :: filter -> SomeFilter params
 
 instance TypeError ('Text "Unknown filter " ':<>: 'ShowType name ':$$:
                     'Text "Allowed ones here: " ':<>: 'ShowType (TyNamedParamsNames origParams)) =>
-         MkSomeFilter name filter origParams '[] where
+         MkSomeFilter' name filter origParams '[] where
     mkSomeFilter = error ":shrug:"
 
 instance {-# OVERLAPPING #-}
          (MkTypeFilter filter fk a, KnownSymbol name, Typeable fk, Typeable a) =>
-         MkSomeFilter name filter origParams ('TyNamedParam name (fk a) ': params) where
+         MkSomeFilter' name filter origParams ('TyNamedParam name (fk a) ': params) where
     mkSomeFilter filter =
         SomeFilter
         { sfName = symbolValT @name
         , sfFilter = mkTypeFilter @filter @fk @a filter
         }
 
-instance MkSomeFilter name filter origParams params =>
-         MkSomeFilter name filter origParams (param ': params) where
+instance MkSomeFilter' name filter origParams params =>
+         MkSomeFilter' name filter origParams (param ': params) where
     mkSomeFilter filter = coerce $ mkSomeFilter @name @filter @origParams @params filter
 
+-- | A constraint required by smart filter constructors based on '?/' operator.
+--
+-- This constraint is satisfied when @SomeFilter params@ allows a filter of type
+-- @filter@ under the name @name@.
+type MkSomeFilter name filter params = MkSomeFilter' name filter params params
+
 -- | "Filter by" operation.
 -- Wraps a filter corresponding to the given name into 'SomeFilter' which can later be
 -- passed to 'mkSomeFilter'.
 (?/)
     :: forall name params filter.
-       MkSomeFilter name filter params params
+       MkSomeFilter name filter params
     => NameLabel name -> filter -> SomeFilter params
 (?/) _ = mkSomeFilter @name @_ @params
 infixr 0 ?/
@@ -124,7 +132,7 @@
 -- | "Filter by matching" operation.
 (?/=)
     :: forall name params filter.
-       MkSomeFilter name (FilterMatching filter) params params
+       MkSomeFilter name (FilterMatching filter) params
     => NameLabel name -> filter -> SomeFilter params
 l ?/= f = l ?/ FilterMatching f
 infixr 0 ?/=
@@ -132,7 +140,7 @@
 -- | Make a comparing filter.
 (?/>), (?/<), (?/>=), (?/<=)
     :: forall name params filter.
-       MkSomeFilter name (FilterComparing filter) params params
+       MkSomeFilter name (FilterComparing filter) params
     => NameLabel name -> filter -> SomeFilter params
 l ?/> f = l ?/ FilterGT f
 l ?/< f = l ?/ FilterLT f
@@ -146,7 +154,7 @@
 -- | Make a simple POSIX regex filter.
 textLike
     :: forall name params text.
-       (MkSomeFilter name (FilterLike text) params params, HasCallStack)
+       (MkSomeFilter name (FilterLike text) params, HasCallStack)
     => NameLabel name -> LText -> SomeFilter params
 l `textLike` p = l ?/ FilterLike @text (CaseSensitivity True) (mkLikePatternUnsafe p)
 infixr 0 `textLike`
@@ -154,7 +162,7 @@
 -- | Make a simple POSIX regex case-insensitive filter.
 textILike
     :: forall name params text.
-       (MkSomeFilter name (FilterLike text) params params, HasCallStack)
+       (MkSomeFilter name (FilterLike text) params, HasCallStack)
     => NameLabel name -> LText -> SomeFilter params
 l `textILike` p = l ?/ FilterLike @text (CaseSensitivity False) (mkLikePatternUnsafe p)
 infixr 0 `textILike`
@@ -162,7 +170,7 @@
 -- | Make a filter that checks whether the given text is included.
 textContains
     :: forall name params text.
-       MkSomeFilter name (FilterLike text) params params
+       MkSomeFilter name (FilterLike text) params
     => NameLabel name -> Text -> SomeFilter params
 l `textContains` p = l ?/ filterContains @text (CaseSensitivity True) p
 infixr 0 `textContains`
@@ -171,7 +179,7 @@
 -- case-insensitive.
 textIContains
     :: forall name params text.
-       MkSomeFilter name (FilterLike text) params params
+       MkSomeFilter name (FilterLike text) params
     => NameLabel name -> Text -> SomeFilter params
 l `textIContains` p = l ?/ filterContains @text (CaseSensitivity False) p
 infixr 0 `textIContains`
@@ -180,7 +188,7 @@
 -- Helpful when newtypes are heavely used in API parameters.
 (?/~)
     :: forall name filter' params filter.
-       (MkSomeFilter name filter' params params, Coercible filter filter')
+       (MkSomeFilter name filter' params, Coercible filter filter')
     => NameLabel name -> filter -> SomeFilter params
 l ?/~ f = l ?/ coerce @_ @filter' f
 
diff --git a/src/Servant/Util/Combinators/Filtering/Filters/General.hs b/src/Servant/Util/Combinators/Filtering/Filters/General.hs
--- a/src/Servant/Util/Combinators/Filtering/Filters/General.hs
+++ b/src/Servant/Util/Combinators/Filtering/Filters/General.hs
@@ -10,7 +10,7 @@
 import qualified Data.Map as M
 import qualified Data.Text as T
 import Fmt (build, listF)
-import Servant (FromHttpApiData (..), ToHttpApiData (..))
+import Servant (FromHttpApiData (..))
 
 import Servant.Util.Combinators.Filtering.Base
 
@@ -57,10 +57,12 @@
             mapM parseUrlPiece vals
 
     autoFilterEncode = \case
-        FilterMatching v    -> (DefFilteringCmd, toQueryParam v)
-        FilterNotMatching v -> ("neq", toQueryParam v)
-        FilterItemsIn vs    -> ("in", "[" <> T.intercalate "," (map toQueryParam vs) <> "]")
-
+        FilterMatching v    -> (DefFilteringCmd, encodeQueryParam v)
+        FilterNotMatching v -> ("neq", encodeQueryParam v)
+        FilterItemsIn vs    -> ("in", encodeFilterItems vs)
+      where
+        encodeFilterItems vs =
+            "[" <> mconcat (intersperse "," $ map encodeQueryParam vs) <> "]"
 
 -- | Support for @(<)@, @(>)@, @(<=)@ and @(>=)@ operations.
 data FilterComparing a
@@ -101,10 +103,10 @@
         ]
 
     autoFilterEncode = \case
-        FilterGT v  -> ("gt", toQueryParam v)
-        FilterLT v  -> ("lt", toQueryParam v)
-        FilterGTE v -> ("gte", toQueryParam v)
-        FilterLTE v -> ("lte", toQueryParam v)
+        FilterGT v  -> ("gt", encodeQueryParam v)
+        FilterLT v  -> ("lt", encodeQueryParam v)
+        FilterGTE v -> ("gte", encodeQueryParam v)
+        FilterLTE v -> ("lte", encodeQueryParam v)
 
 
 -------------------------------------------------------------------------
diff --git a/src/Servant/Util/Combinators/Filtering/Filters/Like.hs b/src/Servant/Util/Combinators/Filtering/Filters/Like.hs
--- a/src/Servant/Util/Combinators/Filtering/Filters/Like.hs
+++ b/src/Servant/Util/Combinators/Filtering/Filters/Like.hs
@@ -15,7 +15,7 @@
 import qualified Data.Map as M
 import qualified Data.Text.Lazy as LT
 import Fmt (Buildable (..), (+|), (|+))
-import Servant (FromHttpApiData (..), ToHttpApiData (..))
+import Servant (FromHttpApiData (..))
 import System.Console.Pretty (Color (..), Style (..), color, style)
 
 import Servant.Util.Combinators.Filtering.Base
@@ -117,6 +117,6 @@
     autoFilterEncode = \case
         FilterLike cs (unLikePattern -> pat)
             | CaseSensitivity True <- cs
-                -> ("like", toQueryParam pat)
+                -> ("like", encodeQueryParam pat)
             | otherwise
-                -> ("ilike", toQueryParam pat)
+                -> ("ilike", encodeQueryParam pat)
diff --git a/src/Servant/Util/Combinators/Sorting/Construction.hs b/src/Servant/Util/Combinators/Sorting/Construction.hs
--- a/src/Servant/Util/Combinators/Sorting/Construction.hs
+++ b/src/Servant/Util/Combinators/Sorting/Construction.hs
@@ -11,7 +11,8 @@
 import Universum
 
 import Data.Default (Default (..))
-import GHC.Exts (IsList (..))
+import qualified GHC.Exts
+import GHC.Exts (IsList)
 import GHC.TypeLits (ErrorMessage (..), KnownSymbol, Symbol, TypeError)
 
 import Servant.Util.Combinators.Sorting.Base
@@ -79,7 +80,7 @@
 mkSortingSpec
     :: ReifySortingItems base
     => [SortingRequestItem provided] -> SortingSpec provided base
-mkSortingSpec = fromList
+mkSortingSpec = GHC.Exts.fromList
 
 -- | By default 'noSorting' is used.
 instance ReifySortingItems base => Default (SortingSpec provided base) where