diff --git a/crdt.cabal b/crdt.cabal
--- a/crdt.cabal
+++ b/crdt.cabal
@@ -3,7 +3,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           crdt
-version:        2.0
+version:        2.1
 synopsis:       Conflict-free replicated data types
 description:    Definitions of CmRDT and CvRDT. Implementations for some classic CRDTs.
 category:       Distributed Systems
@@ -24,7 +24,7 @@
   hs-source-dirs:
       lib
   build-depends:
-      base >= 4.9 && < 4.10
+      base >= 4.9 && < 4.11
     , containers
     , mtl
   exposed-modules:
@@ -48,9 +48,8 @@
   hs-source-dirs:
       test
   build-depends:
-      base >= 4.9 && < 4.10
+      base >= 4.9 && < 4.11
     , containers
-    , QuickCheck
     , tasty
     , tasty-quickcheck
     , crdt
diff --git a/lib/CRDT/Cv/GCounter.hs b/lib/CRDT/Cv/GCounter.hs
--- a/lib/CRDT/Cv/GCounter.hs
+++ b/lib/CRDT/Cv/GCounter.hs
@@ -9,8 +9,7 @@
 import           Data.IntMap.Strict (IntMap)
 import qualified Data.IntMap.Strict as IntMap
 import           Data.Semigroup (Semigroup ((<>)))
-
-import           CRDT.Cv (CvRDT)
+import           Data.Semilattice (Semilattice)
 
 -- | Grow-only counter.
 newtype GCounter a = GCounter (IntMap a)
@@ -19,7 +18,8 @@
 instance Ord a => Semigroup (GCounter a) where
     GCounter x <> GCounter y = GCounter $ IntMap.unionWith max x y
 
-instance Ord a => CvRDT (GCounter a)
+-- | See 'CvRDT'
+instance Ord a => Semilattice (GCounter a)
 
 -- | Increment counter
 increment
diff --git a/lib/CRDT/Cv/PNCounter.hs b/lib/CRDT/Cv/PNCounter.hs
--- a/lib/CRDT/Cv/PNCounter.hs
+++ b/lib/CRDT/Cv/PNCounter.hs
@@ -10,8 +10,8 @@
     ) where
 
 import           Data.Semigroup (Semigroup (..))
+import           Data.Semilattice (Semilattice)
 
-import           CRDT.Cv (CvRDT)
 import           CRDT.Cv.GCounter (GCounter)
 import qualified CRDT.Cv.GCounter as GCounter
 
@@ -29,7 +29,8 @@
 instance Ord a => Semigroup (PNCounter a) where
     PNCounter p1 n1 <> PNCounter p2 n2 = PNCounter (p1 <> p2) (n1 <> n2)
 
-instance Ord a => CvRDT (PNCounter a)
+-- | See 'CvRDT'
+instance Ord a => Semilattice (PNCounter a)
 
 -- | Get value from the state
 query :: Num a => PNCounter a -> a
diff --git a/lib/CRDT/LWW.hs b/lib/CRDT/LWW.hs
--- a/lib/CRDT/LWW.hs
+++ b/lib/CRDT/LWW.hs
@@ -14,9 +14,9 @@
 
 import           Data.Function (on)
 import           Data.Semigroup (Semigroup, (<>))
+import           Data.Semilattice (Semilattice)
 
 import           CRDT.Cm (CausalOrd (..), CmRDT (..))
-import           CRDT.Cv (CvRDT)
 import           LamportClock (Clock (newTimestamp), Timestamp)
 
 -- | Last write wins. Assuming timestamp is unique.
@@ -40,7 +40,8 @@
 instance Semigroup (LWW a) where
     (<>) = max
 
-instance CvRDT (LWW a)
+-- | See 'CvRDT'
+instance Semilattice (LWW a)
 
 -- | Initialize state
 initial :: Clock f => a -> f (LWW a)
diff --git a/test/ArbitraryOrphans.hs b/test/ArbitraryOrphans.hs
--- a/test/ArbitraryOrphans.hs
+++ b/test/ArbitraryOrphans.hs
@@ -5,7 +5,8 @@
 
 module ArbitraryOrphans () where
 
-import           Test.QuickCheck (Arbitrary (..), arbitraryBoundedEnum, oneof)
+import           Test.Tasty.QuickCheck (Arbitrary (..), arbitraryBoundedEnum,
+                                        oneof)
 
 import           CRDT.Cm.Counter (Counter (..))
 import           CRDT.Cm.GSet (GSet (..))