diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+0.2
+---
+* Made compatible with `lens` 4
+
 0.1
 ---
 * Ported `Data.Analytics.Approximate.HyperLogLog` from [analytics](http://github.com/analytics) into a separate package.
diff --git a/hyperloglog.cabal b/hyperloglog.cabal
--- a/hyperloglog.cabal
+++ b/hyperloglog.cabal
@@ -1,6 +1,6 @@
 name:          hyperloglog
 category:      Numeric
-version:       0.1
+version:       0.2
 license:       BSD3
 cabal-version: >= 1.8
 license-file:  LICENSE
@@ -48,22 +48,22 @@
 
 library
   build-depends:
-    approximate               >= 0.1      && < 1,
+    approximate               >= 0.2.1    && < 1,
     base                      >= 4.3      && < 5,
     binary                    >= 0.5      && < 0.8,
     bits                      >= 0.2      && < 1,
     bytes                     >= 0.7      && < 1,
     cereal                    >= 0.3.5    && < 0.4,
     cereal-vector             >= 0.2      && < 0.3,
-    comonad                   >= 3        && < 4,
+    comonad                   >= 4        && < 5,
     deepseq                   >= 1.3      && < 1.5,
     distributive              >= 0.3      && < 1,
     generic-deriving          >= 1.4      && < 1.6,
     hashable                  >= 1.1.2.3  && < 1.3,
     hashable-extras           >= 0.1      && < 1,
-    lens                      >= 3.9      && < 4,
+    lens                      >= 4        && < 5,
     reflection                >= 1.3      && < 2,
-    semigroupoids             >= 3.0.2    && < 4,
+    semigroupoids             >= 4        && < 5,
     semigroups                >= 0.8.4    && < 1,
     safecopy                  >= 0.8.1    && < 0.9,
     tagged                    >= 0.4.5    && < 1,
diff --git a/src/Data/HyperLogLog/Type.hs b/src/Data/HyperLogLog/Type.hs
--- a/src/Data/HyperLogLog/Type.hs
+++ b/src/Data/HyperLogLog/Type.hs
@@ -37,6 +37,7 @@
     HyperLogLog(..)
   , HasHyperLogLog(..)
   , size
+  , insert
   , intersectionSize
   , cast
   ) where
@@ -81,10 +82,10 @@
 --
 -- Let's count a list of unique items and get the latest estimate:
 --
--- >>> size (foldr cons mempty [1..10] :: HyperLogLog $(4))
+-- >>> size (foldr insert mempty [1..10] :: HyperLogLog $(4))
 -- Approximate {_confidence = 0.9972, _lo = 2, _estimate = 11, _hi = 20}
 --
--- Note how 'cons' can be used to add new observations to the
+-- Note how 'insert' can be used to add new observations to the
 -- approximate counter.
 newtype HyperLogLog p = HyperLogLog { runHyperLogLog :: V.Vector Rank }
     deriving (Eq, Show, Generic)
@@ -113,21 +114,15 @@
   mappend = (<>)
   {-# INLINE mappend #-}
 
-instance (Profunctor p, Bifunctor p, Functor f, ReifiesConfig s, Hashable a, s ~ t, a ~ b) => Cons p f (HyperLogLog s) (HyperLogLog t) a b where
-  _Cons = unto go where
-    go (a,m@(HyperLogLog v)) = HyperLogLog $ V.modify (\x -> do old <- MV.read x bk; when (rnk > old) $ MV.write x bk rnk) v where
-      !h = w32 (hash a)
-      !bk = calcBucket m h
-      !rnk = calcRank m h
-  {-# INLINE _Cons #-}
-
-instance (Profunctor p, Bifunctor p, Functor f, ReifiesConfig s, Hashable a, s ~ t, a ~ b) => Snoc p f (HyperLogLog s) (HyperLogLog t) a b where
-  _Snoc = unto go where
-    go (m@(HyperLogLog v), a) = HyperLogLog $ V.modify (\x -> do old <- MV.read x bk; when (rnk > old) $ MV.write x bk rnk) v where
-      !h = w32 (hash a)
-      !bk = calcBucket m h
-      !rnk = calcRank m h
-  {-# INLINE _Snoc #-}
+insert :: (ReifiesConfig s, Hashable a) => a -> HyperLogLog s -> HyperLogLog s
+insert a m@(HyperLogLog v) = HyperLogLog $ V.modify (\x -> do
+    old <- MV.read x bk
+    when (rnk > old) $ MV.write x bk rnk
+  ) v where
+  !h = w32 (hash a)
+  !bk = calcBucket m h
+  !rnk = calcRank m h
+{-# INLINE insert #-}
 
 -- | Approximate size of our set
 size :: ReifiesConfig p => HyperLogLog p -> Approximate Int64