diff --git a/src/Yesod/Form/Bootstrap4.hs b/src/Yesod/Form/Bootstrap4.hs
--- a/src/Yesod/Form/Bootstrap4.hs
+++ b/src/Yesod/Form/Bootstrap4.hs
@@ -1,5 +1,4 @@
 {-# LANGUAGE NamedFieldPuns    #-}
-{-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE QuasiQuotes       #-}
 {-# LANGUAGE TypeFamilies      #-}
@@ -21,7 +20,13 @@
     , BootstrapSubmit(..)
     ) where
 
-import           ClassyPrelude.Yesod
+import           Control.Arrow
+import           Data.Maybe
+import           Data.String
+import           Data.Text
+import           Text.Shakespeare.I18N
+import           Yesod.Core
+import           Yesod.Core.Types
 import           Yesod.Form
 
 bfs :: RenderMessage site msg => msg -> FieldSettings site
@@ -48,7 +53,7 @@
 
 addClass :: Text -> [(Text, Text)] -> [(Text, Text)]
 addClass klass []                    = [("class", klass)]
-addClass klass (("class", old):rest) = ("class", concat [old, " ", klass]) : rest
+addClass klass (("class", old):rest) = ("class", Data.Text.concat [old, " ", klass]) : rest
 addClass klass (other         :rest) = other : addClass klass rest
 
 data BootstrapGridOptions = ColXs !Int | ColSm !Int | ColMd !Int | ColLg !Int | ColXl !Int
@@ -130,7 +135,7 @@
     return (res, widget)
 
 -- | (Internal) Render a help widget for tooltips and errors.
-helpWidget :: FieldView site -> WidgetT site IO ()
+helpWidget :: FieldView site -> WidgetFor site ()
 helpWidget view = [whamlet|
     $maybe err <- fvErrors view
       <div .form-control-feedback>#{err}
diff --git a/yesod-form-bootstrap4.cabal b/yesod-form-bootstrap4.cabal
--- a/yesod-form-bootstrap4.cabal
+++ b/yesod-form-bootstrap4.cabal
@@ -2,10 +2,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 6e5c9578eafcff708e739d119bf37446d108c64b8a85c4f3acbc39779cf8804e
+-- hash: d3d64533622b0d3d260186735cd3d0b768de41866516b2d9f91672d9b0cbcc47
 
 name:           yesod-form-bootstrap4
-version:        0.1.1
+version:        1.0.0
 synopsis:       renderBootstrap4
 category:       Web
 homepage:       https://github.com/ncaq/yesod-form-bootstrap4#readme
@@ -26,7 +26,9 @@
       src
   build-depends:
       base >=4.7 && <5
-    , classy-prelude-yesod
+    , shakespeare
+    , text
+    , yesod-core
     , yesod-form
   exposed-modules:
       Yesod.Form.Bootstrap4