diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+### 3.8.1 [2019.06.03]
+* Require `quickcheck-instances-0.3.21` or later.
+
 ## 3.8 [2019.05.02]
 * Support GHC 8.8.
 * Add a `TextShow` instance for `ShortText` (from the `text-short` package) in
@@ -26,7 +29,7 @@
 * GHC 8.4 fixes
 
 ### 3.6.2 [2017.06.18]
-* Require `QuickCheck-2.10`/`quickcheck-instances-0.13.6` or later
+* Require `QuickCheck-2.10`/`quickcheck-instances-0.3.16` or later
 
 ### 3.6.1 [2017.06.04]
 * Drop support for GHC 7.0 and 7.2
diff --git a/tests/Instances/Data/Time.hs b/tests/Instances/Data/Time.hs
--- a/tests/Instances/Data/Time.hs
+++ b/tests/Instances/Data/Time.hs
@@ -21,11 +21,7 @@
 #if MIN_VERSION_time(1,8,0)
 import Data.Time.Clock.System (SystemTime(..))
 import GHC.Generics (Generic)
-import Instances.Utils.GenericArbitrary (genericArbitrary)
-import Test.QuickCheck (Arbitrary(..))
-
-instance Arbitrary SystemTime where
-    arbitrary = genericArbitrary
+import Test.QuickCheck.Instances.Time ()
 
 deriving instance Generic SystemTime
 #endif
diff --git a/text-show-instances.cabal b/text-show-instances.cabal
--- a/text-show-instances.cabal
+++ b/text-show-instances.cabal
@@ -1,5 +1,5 @@
 name:                text-show-instances
-version:             3.8
+version:             3.8.1
 synopsis:            Additional instances for text-show
 description:         @text-show-instances@ is a supplemental library to @text-show@
                      that provides additional @Show@ instances for data types in
@@ -267,7 +267,7 @@
                      , old-time              >= 1.1    && < 1.2
                      , pretty                >= 1.1.1  && < 1.2
                      , QuickCheck            >= 2.12   && < 2.14
-                     , quickcheck-instances  >= 0.3.19 && < 0.4
+                     , quickcheck-instances  >= 0.3.21 && < 0.4
                      , random                >= 1.0.1  && < 1.2
                      , tagged                >= 0.4.4  && < 1
                      , text-short            >= 0.1    && < 0.2