diff --git a/benchmarks/aeson/HashMapExts.hs b/benchmarks/aeson/HashMapExts.hs
deleted file mode 100644
--- a/benchmarks/aeson/HashMapExts.hs
+++ /dev/null
@@ -1,35 +0,0 @@
-{-# LANGUAGE QuasiQuotes #-}
-{-# LANGUAGE MagicHash #-}
-{-# LANGUAGE UnboxedTuples #-}
-module HashMapExts where
-
-import Data.HashMap.Strict (HashMap)
-import Data.Monoid
-import GHC.Exts (SmallArray#, sizeofSmallArray#, indexSmallArray#, Int(..))
-import Unsafe.TrueName (truename)
-
-foldMapWithKey :: (Monoid m) => (k -> a -> m) -> HashMap k a -> m
-foldMapWithKey f = go
-  where
-    go hm = case hm of
-      [truename| ''HashMap Empty |] -> mempty
-      [truename| ''HashMap BitmapIndexed | _ ary |] -> foldMapArray go ary
-      [truename| ''HashMap Full | ary |] -> foldMapArray go ary
-      [truename| ''HashMap Collision | _ ary |] -> foldMapArray leaf ary
-      [truename| ''HashMap Leaf | _ l |] -> leaf l
-
-    leaf [truename| ''HashMap Leaf Leaf L | k v|]  = f k v
-{-# INLINE foldMapWithKey #-}
-
-foldMapArray :: (Monoid m) =>
-    (a -> m) -> [truename| ''HashMap Full Array |] a -> m
-foldMapArray f [truename| ''HashMap Full Array Array | a |] = foldMapArray' f a
-
-foldMapArray' :: (Monoid m) => (a -> m) -> SmallArray# a -> m
-foldMapArray' f arr = go 0
-  where
-    go k@(I# k#)
-      | k >= I# (sizeofSmallArray# arr) = mempty
-      | otherwise = case indexSmallArray# arr k# of
-        (# v #) -> f v <> go (k + 1)
-{-# INLINE foldMapArray' #-}
diff --git a/benchmarks/aeson/template.hs b/benchmarks/aeson/template.hs
--- a/benchmarks/aeson/template.hs
+++ b/benchmarks/aeson/template.hs
@@ -11,6 +11,7 @@
 
 import Data.Aeson
 import qualified Data.ByteString.Lazy as L
+import qualified Data.HashMap.Strict as H
 import Data.Monoid
 import qualified Data.Scientific as Sci
 import qualified Data.Text as T
@@ -18,7 +19,6 @@
 import qualified Data.Vector as V
 
 import LIB
-import HashMapExts
 
 valueToLazyByteString :: Value -> L.ByteString
 valueToLazyByteString = toLazyByteString . fromValue
@@ -51,7 +51,7 @@
 fromNumber = either doubleDec integerDec . Sci.floatingOrInteger
 
 fromObject :: Object -> Builder
-fromObject obj = char8 '{' <> foldMapWithKey f obj <> char8 '}'
+fromObject obj = char8 '{' <> H.foldMapWithKey f obj <> char8 '}'
   where
       f k v =
         fromString k <> char8 ':' <> fromValue v
diff --git a/fast-builder.cabal b/fast-builder.cabal
--- a/fast-builder.cabal
+++ b/fast-builder.cabal
@@ -1,5 +1,5 @@
 name:                fast-builder
-version:             0.1.2.0
+version:             0.1.2.1
 synopsis:            Fast ByteString Builder
 description:         An efficient implementation of ByteString builder. It should be faster than
                      the standard implementation in most cases.
@@ -16,7 +16,7 @@
 extra-source-files:  benchmarks/aeson/*.hs
                      benchmarks/aeson/*.json
 cabal-version:       >=1.10
-tested-with:         GHC == 8.2.2, GHC == 8.4.4, GHC == 8.6.5, GHC == 8.8.1
+tested-with:         GHC ==8.0.2 || ==8.2.2 || ==8.4.4 || ==8.6.5 || ==8.8.3 || ==8.10.1
 
 library
   exposed-modules:     Data.ByteString.FastBuilder,
@@ -25,7 +25,7 @@
   other-modules:       Data.ByteString.FastBuilder.Internal.Prim
 
   -- other-extensions:
-  build-depends:       base >= 4.8 && < 4.14, bytestring >= 0.10.6.0, ghc-prim
+  build-depends:       base >= 4.8 && < 4.15, bytestring >= 0.10.6.0, ghc-prim
   -- hs-source-dirs:
   default-language:    Haskell2010
   ghc-options:         -Wall
@@ -34,11 +34,11 @@
   type:                exitcode-stdio-1.0
   main-is:             main.hs
   hs-source-dirs:      benchmarks/aeson
-  other-modules:       Fast, Bstr, HashMapExts
+  other-modules:       Fast, Bstr
   include-dirs:        benchmarks/aeson
   build-depends:       base, fast-builder, aeson, criterion, bytestring,
-    scientific, text, vector, deepseq, unordered-containers, ghc-prim,
-    template-haskell, true-name >= 0.1.0.0
+    scientific, text, vector, deepseq, ghc-prim, template-haskell,
+    unordered-containers >= 0.2.11.0
   ghc-options:         -fsimpl-tick-factor=120
   ghc-options:         -Wall -threaded -g -rtsopts
   default-language:    Haskell2010