diff --git a/Setup.hs b/Setup.hs
deleted file mode 100644
--- a/Setup.hs
+++ /dev/null
@@ -1,2 +0,0 @@
-import Distribution.Simple
-main = defaultMain
diff --git a/sdp.cabal b/sdp.cabal
--- a/sdp.cabal
+++ b/sdp.cabal
@@ -1,5 +1,5 @@
 name:          sdp
-version:       0.2
+version:       0.2.0.1
 category:      Data Structures
 
 synopsis:      Simple Data Processing
@@ -16,6 +16,20 @@
 build-type:    Simple
 cabal-version: >=1.10
 
+tested-with:
+  -- lts-7.24
+  GHC == 8.0.1,
+  -- lts-9.21
+  GHC == 8.0.2,
+  -- lts-11.22
+  GHC == 8.2.2,
+  -- lts-12.26
+  GHC == 8.4.4,
+  -- lts-18.8
+  GHC == 8.10.6,
+  -- lts-18.13
+  GHC == 8.10.7
+
 source-repository head
   type: git
   location: https://github.com/andreymulik/sdp
@@ -34,9 +48,9 @@
   ghc-options:      -O2 -Wall -Wcompat -Wno-orphans
   
   build-depends:
-    base               >= 4.9   && < 5,
-    ghc-prim           >= 0.5.3 && < 0.7,
-    data-default-class >= 0.1   && < 0.2
+    base               >= 4.9 && <   5,
+    ghc-prim           >= 0.5 && < 0.7,
+    data-default-class >= 0.1 && < 0.2
   
   exposed-modules:
     SDP.SafePrelude
@@ -112,4 +126,5 @@
     
     Text.Show.SDP
     Text.Read.SDP
+
 
diff --git a/src/SDP/Index.hs b/src/SDP/Index.hs
--- a/src/SDP/Index.hs
+++ b/src/SDP/Index.hs
@@ -385,8 +385,12 @@
 instance Index CPtrdiff   where offset = offsetIntegral
 instance Index CSigAtomic where offset = offsetIntegral
 
+#if MIN_VERSION_base(4,10,0)
+-- | @since base-4.10.0.0
+instance Index CBool where offset = offsetIntegral; defaultBounds = defaultBoundsUnsign
+#endif
+
 instance Index CSize      where offset = offsetIntegral; defaultBounds = defaultBoundsUnsign
-instance Index CBool      where offset = offsetIntegral; defaultBounds = defaultBoundsUnsign
 instance Index CUChar     where offset = offsetIntegral; defaultBounds = defaultBoundsUnsign
 instance Index CUShort    where offset = offsetIntegral; defaultBounds = defaultBoundsUnsign
 
@@ -555,6 +559,7 @@
 
 emptyEx :: String -> a
 emptyEx =  throw . EmptyRange . showString "in SDP.Index."
+
 
 
 
diff --git a/src/SDP/Linear.hs b/src/SDP/Linear.hs
--- a/src/SDP/Linear.hs
+++ b/src/SDP/Linear.hs
@@ -1,6 +1,6 @@
 {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances #-}
 {-# LANGUAGE PatternSynonyms, ViewPatterns, BangPatterns, DefaultSignatures #-}
-{-# LANGUAGE Trustworthy, TypeOperators, TypeFamilies, ConstraintKinds #-}
+{-# LANGUAGE Trustworthy, TypeOperators, TypeFamilies, ConstraintKinds, CPP #-}
 
 {- |
     Module      :  SDP.Linear
@@ -558,9 +558,18 @@
       
       > splitsOn "fo" "foobar bazfoobar1" == ["","obar baz","obar1"]
     -}
-    default splitsOn :: (Eq e, Bordered s i) => s -> s -> [s]
     splitsOn :: (Eq e) => s -> s -> [s]
+#if __GLASGOW_HASKELL__ >= 820
+    default splitsOn :: (Eq e, Bordered s i) => s -> s -> [s]
     splitsOn sub line = drop (sizeOf sub) <$> parts (infixes sub line) line
+    -- ghc-8.0.1 has bug in default signatures, so this can be used with it
+#else
+    {-
+      Not tested, but should be significantly slower than the definitions below.
+      If you plan to support ghc-8.0.1, override splitsOn in all your instances.
+    -}
+    splitsOn sub line = fromList <$> splitsOn (listL sub) (listL line)
+#endif
     
     {- |
       @replaceBy sub new line@ replace every non-overlapping occurrence of @sub@
@@ -915,6 +924,7 @@
 -}
 ascending :: (Split s e, Sort s e, Ord e) => s -> [Int] -> Bool
 ascending =  all sorted ... flip splits
+
 
 
 
diff --git a/src/SDP/Prim/SArray.hs b/src/SDP/Prim/SArray.hs
--- a/src/SDP/Prim/SArray.hs
+++ b/src/SDP/Prim/SArray.hs
@@ -65,7 +65,6 @@
 import Data.Typeable
 import Data.Coerce
 import Data.String
-import Data.Proxy
 
 import Text.Read
 
@@ -147,7 +146,7 @@
     isNull = \ (SArray# c _ _) -> c == 0
 
 instance Semigroup (SArray# e) where (<>) = (++)
-instance Monoid    (SArray# e) where mempty = Z
+instance Monoid    (SArray# e) where mempty = Z; mappend = (<>)
 instance Default   (SArray# e) where def = Z
 
 instance Estimate (SArray# e)
@@ -1206,6 +1205,10 @@
 ascsBounds :: (Ord a) => [(a, b)] -> (a, a)
 ascsBounds =  \ ((x, _) : xs) -> foldr (\ (e, _) (mn, mx) -> (min mn e, max mx e)) (x, x) xs
 
+-- | In base-4.9 'asProxyTypeOf' has less general type @a -> Proxy a -> a@.
+asProxyTypeOf :: a -> proxy a -> a
+asProxyTypeOf =  const
+
 --------------------------------------------------------------------------------
 
 undEx :: String -> a
@@ -1222,4 +1225,6 @@
 
 unreachEx :: String -> a
 unreachEx =  throw . UnreachableException . showString "in SDP.Prim.SArray."
+
+
 
diff --git a/src/SDP/Prim/SBytes.hs b/src/SDP/Prim/SBytes.hs
--- a/src/SDP/Prim/SBytes.hs
+++ b/src/SDP/Prim/SBytes.hs
@@ -145,7 +145,7 @@
     isNull es = case es of {(SBytes# 0 _ _) -> True; _ -> False}
 
 instance (Unboxed e) => Semigroup (SBytes# e) where (<>) = (++)
-instance (Unboxed e) => Monoid    (SBytes# e) where mempty = Z
+instance (Unboxed e) => Monoid    (SBytes# e) where mempty = Z; mappend = (<>)
 
 instance Default (SBytes# e)
   where
diff --git a/src/SDP/SafePrelude.hs b/src/SDP/SafePrelude.hs
--- a/src/SDP/SafePrelude.hs
+++ b/src/SDP/SafePrelude.hs
@@ -1,5 +1,5 @@
 {-# OPTIONS_HADDOCK ignore-exports #-}
-{-# LANGUAGE Safe #-}
+{-# LANGUAGE Safe, CPP #-}
 
 {- |
     Module      :  SDP.SafePrelude
@@ -42,6 +42,10 @@
   
   module Prelude,
   
+#if !MIN_VERSION_base(4,11,0)
+  Semigroup (..),
+#endif
+  
   -- * Combinators
   on, (?), (?+), (?-), (?^), (?:), (+?), (...), (<=<<), (>>=>), (>>=<<)
 )
@@ -67,6 +71,10 @@
 import SDP.Comparing
 import SDP.Estimate
 
+#if !MIN_VERSION_base(4,11,0)
+import Data.Semigroup ( Semigroup (..) ) -- For base >= 4.9 && < 4.11
+#endif
+
 import Data.Functor.Classes
 import Data.Bifunctor
 import Data.Foldable hiding ( foldrM, foldlM, concat, concatMap )
@@ -164,7 +172,4 @@
 -- | 'stToMIO' is just @'liftIO' . 'stToIO'@.
 stToMIO :: (MonadIO io) => ST RealWorld e -> io e
 stToMIO =  liftIO . stToIO
-
-
-
 
diff --git a/src/SDP/Shape.hs b/src/SDP/Shape.hs
--- a/src/SDP/Shape.hs
+++ b/src/SDP/Shape.hs
@@ -202,7 +202,12 @@
 instance Shape CUIntMax
 
 instance Shape CSize
+
+#if MIN_VERSION_base(4,10,0)
+-- | @since base-4.10.0.0
 instance Shape CBool
+#endif
+
 instance Shape CPtrdiff
 instance Shape CSigAtomic
 
diff --git a/src/SDP/Templates/AnyBorder.hs b/src/SDP/Templates/AnyBorder.hs
--- a/src/SDP/Templates/AnyBorder.hs
+++ b/src/SDP/Templates/AnyBorder.hs
@@ -127,7 +127,7 @@
     lzero  = withBounds lzero
 
 instance (Linear1 (AnyBorder rep i) e) => Semigroup (AnyBorder rep i e) where (<>) = (++)
-instance (Linear1 (AnyBorder rep i) e) => Monoid    (AnyBorder rep i e) where mempty = Z
+instance (Linear1 (AnyBorder rep i) e) => Monoid    (AnyBorder rep i e) where mempty = Z; mappend = (<>)
 instance (Linear1 (AnyBorder rep i) e) => Default   (AnyBorder rep i e) where def = Z
 
 instance (Index i) => Estimate (AnyBorder rep i e)
diff --git a/src/SDP/Templates/AnyChunks.hs b/src/SDP/Templates/AnyChunks.hs
--- a/src/SDP/Templates/AnyChunks.hs
+++ b/src/SDP/Templates/AnyChunks.hs
@@ -136,7 +136,7 @@
   where
     AnyChunks xs <> AnyChunks ys = AnyChunks (xs ++ ys)
 
-instance Monoid  (AnyChunks rep e) where mempty = AnyChunks []
+instance Monoid  (AnyChunks rep e) where mempty = AnyChunks []; mappend = (<>)
 instance Default (AnyChunks rep e) where def    = AnyChunks []
 
 instance (Bordered1 rep Int e) => Estimate (AnyChunks rep e)
diff --git a/src/SDP/Unboxed.hs b/src/SDP/Unboxed.hs
--- a/src/SDP/Unboxed.hs
+++ b/src/SDP/Unboxed.hs
@@ -457,7 +457,12 @@
 SDP_DERIVE_FOREIGN_UNBOXED(CSUSeconds)
 
 SDP_DERIVE_FOREIGN_UNBOXED(CSize)
+
+#if MIN_VERSION_base(4,10,0)
+-- | @since base-4.10.0.0
 SDP_DERIVE_FOREIGN_UNBOXED(CBool)
+#endif
+
 SDP_DERIVE_FOREIGN_UNBOXED(CFloat)
 SDP_DERIVE_FOREIGN_UNBOXED(CDouble)
 SDP_DERIVE_FOREIGN_UNBOXED(CSigAtomic)