diff --git a/Test/TestMonoidSubclasses.hs b/Test/TestMonoidSubclasses.hs
--- a/Test/TestMonoidSubclasses.hs
+++ b/Test/TestMonoidSubclasses.hs
@@ -773,7 +773,7 @@
    arbitrary = fmap ByteStringUTF8 arbitrary
 
 instance (Arbitrary a, MonoidNull a, PositiveMonoid a) => Arbitrary (Concat a) where
-   arbitrary = fmap Concat.concatenate arbitrary
+   arbitrary = fmap (foldMap pure) (arbitrary :: Gen [a])
 
 instance (Arbitrary a, FactorialMonoid a) => Arbitrary (Measured a) where
    arbitrary = fmap Measured.measure arbitrary
@@ -791,7 +791,7 @@
    coarbitrary (ByteStringUTF8 bs) = coarbitrary bs
 
 instance CoArbitrary a => CoArbitrary (Concat a) where
-   coarbitrary = coarbitrary . Concat.extract
+   coarbitrary = coarbitrary . toList
 
 instance CoArbitrary a => CoArbitrary (Measured a) where
    coarbitrary = coarbitrary . Measured.extract
diff --git a/monoid-subclasses.cabal b/monoid-subclasses.cabal
--- a/monoid-subclasses.cabal
+++ b/monoid-subclasses.cabal
@@ -1,5 +1,5 @@
 Name:                monoid-subclasses
-Version:             0.4.3
+Version:             0.4.3.1
 Cabal-Version:       >= 1.10
 Build-Type:          Simple
 Synopsis:            Subclasses of Monoid
@@ -27,7 +27,7 @@
                      Data.Monoid.Instances.Measured, Data.Monoid.Instances.Positioned, Data.Monoid.Instances.Stateful
   Build-Depends:     base >= 4.5 && < 5,
                      bytestring >= 0.9 && < 1.0, containers >= 0.5.7.0 && < 0.6, text >= 0.11 && < 1.3,
-                     primes == 0.2.*, vector >= 0.9 && < 0.12
+                     primes == 0.2.*, vector >= 0.9 && < 0.13
   GHC-options:       -Wall
   default-language:  Haskell2010
 
@@ -35,7 +35,7 @@
   Type:              exitcode-stdio-1.0
   Build-Depends:     base >= 4.5 && < 5,
                      bytestring >= 0.9 && < 1.0, containers >= 0.5.7.0 && < 0.6, text >= 0.11 && < 1.3,
-                     vector >= 0.9 && < 0.12, primes == 0.2.*,
+                     vector >= 0.9 && < 0.13, primes == 0.2.*,
                      QuickCheck >= 2.9 && < 3, quickcheck-instances >= 0.3.12 && <0.4,
                      tasty >= 0.7, tasty-quickcheck >= 0.7,
                      monoid-subclasses