diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,9 @@
+0.3.5 [2021.11.16]
+------------------
+* Add `Eq1` instances for `Approximate` and `Mass`.
+* Allow building with `hashable-1.4.*`.
+* Drop support for pre-8.0 versions of GHC.
+
 0.3.4 [2021.02.21]
 ------------------
 * Fix the build with `safecopy-0.10.4` or later.
diff --git a/approximate.cabal b/approximate.cabal
--- a/approximate.cabal
+++ b/approximate.cabal
@@ -1,6 +1,6 @@
 name:          approximate
 category:      Numeric
-version:       0.3.4
+version:       0.3.5
 license:       BSD3
 cabal-version: >= 1.10
 license-file:  LICENSE
@@ -11,16 +11,14 @@
 bug-reports:   http://github.com/analytics/approximate/issues
 copyright:     Copyright (C) 2013 Edward A. Kmett
 build-type:    Simple
-tested-with:   GHC == 7.4.2
-             , GHC == 7.6.3
-             , GHC == 7.8.4
-             , GHC == 7.10.3
-             , GHC == 8.0.2
+tested-with:   GHC == 8.0.2
              , GHC == 8.2.2
              , GHC == 8.4.4
              , GHC == 8.6.5
-             , GHC == 8.8.3
-             , GHC == 8.10.1
+             , GHC == 8.8.4
+             , GHC == 8.10.7
+             , GHC == 9.0.1
+             , GHC == 9.2.1
 synopsis:      Approximate discrete values and numbers
 description:   This package provides approximate discrete values and numbers.
 
@@ -43,21 +41,21 @@
 
 library
   build-depends:
-    base                      >= 4.3      && < 5,
+    base                      >= 4.9      && < 5,
     binary                    >= 0.5      && < 0.9,
     bytes                     >= 0.7      && < 1,
     cereal                    >= 0.3.5    && < 0.6,
     comonad                   >= 3        && < 6,
     deepseq                   >= 1.3      && < 1.5,
     ghc-prim,
-    hashable                  >= 1.2.5    && < 1.4,
+    hashable                  >= 1.2.5    && < 1.5,
     lens                      >= 3.9      && < 6,
     log-domain,
     pointed                   >= 3        && < 6,
     semigroupoids             >= 3.0.2    && < 6,
     semigroups                >= 0.8.4    && < 1,
     safecopy                  >= 0.8.1    && < 0.11,
-    vector                    >= 0.9      && < 0.13
+    vector                    >= 0.12.1.2 && < 0.13
 
   if flag(herbie)
     build-depends: HerbiePlugin >= 0.1 && < 0.2
@@ -70,10 +68,7 @@
     Data.Approximate.Mass
     Data.Approximate.Numerics
 
-  if impl(ghc >= 7.4 && < 7.6)
-    build-depends: ghc-prim
-
   c-sources: cbits/fast.c
-  ghc-options: -Wall -fwarn-tabs -O2
+  ghc-options: -Wall -Wtabs -O2
   hs-source-dirs: src
   default-language: Haskell2010
diff --git a/src/Data/Approximate/Mass.hs b/src/Data/Approximate/Mass.hs
--- a/src/Data/Approximate/Mass.hs
+++ b/src/Data/Approximate/Mass.hs
@@ -17,9 +17,6 @@
   , (|?), (&?), (^?)
   ) where
 
-#if __GLASGOW_HASKELL__ < 710
-import Control.Applicative
-#endif
 import Control.Comonad
 import Control.DeepSeq
 import Control.Monad
@@ -27,10 +24,8 @@
 import Data.Bytes.Serial as Bytes
 import Data.Copointed
 import Data.Data
-#if __GLASGOW_HASKELL__ < 710
-import Data.Foldable
-#endif
 import Data.Functor.Bind
+import Data.Functor.Classes
 import Data.Functor.Extend
 import Data.Hashable (Hashable(..))
 import Data.Hashable.Lifted (Hashable1(..))
@@ -40,12 +35,10 @@
 import Data.Semigroup
 #endif
 import Data.Serialize as Serialize
-#if __GLASGOW_HASKELL__ < 710
-import Data.Traversable
-#endif
-import Data.Vector.Generic as G
-import Data.Vector.Generic.Mutable as M
-import Data.Vector.Unboxed as U
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Generic.Mutable as M
+import qualified Data.Vector.Unboxed as U
+import Data.Vector.Unboxed (Unbox)
 import GHC.Generics
 import Numeric.Log
 
@@ -74,7 +67,7 @@
 -- Mass 0.669921875 "zzz"
 --
 data Mass a = Mass {-# UNPACK #-} !(Log Double) a
-  deriving (Eq,Ord,Show,Read,Typeable,Data,Generic)
+  deriving (Eq,Ord,Show,Read,Data,Generic)
 
 instance Binary a => Binary (Mass a) where
   put (Mass p a) = Binary.put p >> Binary.put a
@@ -91,6 +84,9 @@
   getCopy = contain Serialize.get
   putCopy = contain . Serialize.put
 
+instance Eq1 Mass where
+    liftEq eq (Mass p a) (Mass q b) = p == q && eq a b
+
 instance Hashable a => Hashable (Mass a)
 instance Hashable1 Mass where
     liftHashWithSalt h s (Mass m x) = hashWithSalt s m `h` x
@@ -139,10 +135,8 @@
   {-# INLINE basicUnsafeMove #-}
   basicUnsafeGrow (MV_Mass v) n = MV_Mass `liftM` M.basicUnsafeGrow v n
   {-# INLINE basicUnsafeGrow #-}
-#if MIN_VERSION_vector(0,11,0)
   basicInitialize (MV_Mass v) = M.basicInitialize v
   {-# INLINE basicInitialize #-}
-#endif
 
 instance Unbox a => G.Vector U.Vector (Mass a) where
   basicUnsafeFreeze (MV_Mass v) = V_Mass `liftM` G.basicUnsafeFreeze v
@@ -192,8 +186,10 @@
 instance Monoid a => Monoid (Mass a) where
   mempty = Mass 1 mempty
   {-# INLINE mempty #-}
+#if !(MIN_VERSION_base(4,11,0))
   mappend (Mass p a) (Mass q b) = Mass (p * q) (mappend a b)
   {-# INLINE mappend #-}
+#endif
 
 instance Semigroup a => Semigroup (Mass a) where
   Mass p a <> Mass q b = Mass (p * q) (a <> b)
diff --git a/src/Data/Approximate/Type.hs b/src/Data/Approximate/Type.hs
--- a/src/Data/Approximate/Type.hs
+++ b/src/Data/Approximate/Type.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE FunctionalDependencies #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE TemplateHaskell #-}
@@ -31,19 +30,18 @@
 import Data.Bytes.Serial as Bytes
 import Data.Copointed
 import Data.Data
-#if __GLASGOW_HASKELL__ < 710
-import Data.Foldable
-#endif
 import Data.Functor.Apply
+import Data.Functor.Classes
 import Data.Hashable (Hashable(..))
 import Data.Hashable.Lifted (Hashable1(..))
 import Data.Monoid
 import Data.Pointed
 import Data.SafeCopy
 import Data.Serialize as Serialize
-import Data.Vector.Generic as G
-import Data.Vector.Generic.Mutable as M
-import Data.Vector.Unboxed as U
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Generic.Mutable as M
+import qualified Data.Vector.Unboxed as U
+import Data.Vector.Unboxed (Unbox)
 import GHC.Generics
 import Numeric.Log
 
@@ -53,7 +51,7 @@
 data Approximate a = Approximate
   { _confidence :: {-# UNPACK #-} !(Log Double)
   , _lo, _estimate, _hi :: a
-  } deriving (Eq,Show,Read,Typeable,Data,Generic)
+  } deriving (Eq,Show,Read,Data,Generic)
 
 makeClassy ''Approximate
 
@@ -72,6 +70,10 @@
   getCopy = contain Serialize.get
   putCopy = contain . Serialize.put
 
+instance Eq1 Approximate where
+    liftEq eq (Approximate p la ma ha) (Approximate q lb mb hb) =
+      p == q && eq la lb && eq ma mb && eq ha hb
+
 instance Hashable a => Hashable (Approximate a)
 instance Hashable1 Approximate where
     liftHashWithSalt h s (Approximate c low est high) =
@@ -116,10 +118,8 @@
   {-# INLINE basicUnsafeMove #-}
   basicUnsafeGrow (MV_Approximate v) n = MV_Approximate `liftM` M.basicUnsafeGrow v n
   {-# INLINE basicUnsafeGrow #-}
-#if MIN_VERSION_vector(0,11,0)
   basicInitialize (MV_Approximate v) = M.basicInitialize v
   {-# INLINE basicInitialize #-}
-#endif
 
 instance Unbox a => G.Vector U.Vector (Approximate a) where
   basicUnsafeFreeze (MV_Approximate v) = V_Approximate `liftM` G.basicUnsafeFreeze v