diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+# 0.1.2.1
+
+- Require cabal-version: 2.0
+- The library itself is unchanged. Update of the test code only.
+
 # 0.1.2.0
 
 - Fail correctly, with appropriate error message, when deriving Matchable
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 generate instances of `Matchable` and `Bimatchable` type classes,
 which are from `matchable` package.
 
-### Example
+### Examples
 
 ``` haskell
 {-# LANGUAGE DeriveFunctor #-}
@@ -36,23 +36,37 @@
 
 -- Most simple case
 data BiF a b = BiF0 | BiF1 a b
+  deriving (Show, Eq)
 
+$(deriveBimatchable ''BiF)
+
+instance Eq a => Eq1 (BiF a) where
+  liftEq = liftEq2Default (==)
+
 instance Eq2 BiF where
   liftEq2 = liftEq2Default
 
+instance Functor (BiF a) where
+  fmap = bimapRecovered id
+
 instance Bifunctor BiF where
   bimap = bimapRecovered
 
-$(deriveBimatchable ''BiF)
-
 -- Test case for using [], tuple, and another Bimatchable instance
 data BiG a b = BiG0 | BiG1 [a] [b] | BiG2 (Int, BiF a b)
+  deriving (Show, Eq)
 
+$(deriveBimatchable ''BiG)
+
+instance Eq a => Eq1 (BiG a) where
+  liftEq = liftEq2Default (==)
+
 instance Eq2 BiG where
   liftEq2 = liftEq2Default
 
+instance Functor (BiG a) where
+  fmap = bimapRecovered id
+
 instance Bifunctor BiG where
   bimap = bimapRecovered
-
-$(deriveBimatchable ''BiG)
 ```
diff --git a/matchable-th.cabal b/matchable-th.cabal
--- a/matchable-th.cabal
+++ b/matchable-th.cabal
@@ -1,5 +1,5 @@
 name:                matchable-th
-version:             0.1.2.0
+version:             0.1.2.1
 synopsis:            Generates Matchable instances using TemplateHaskell
 description:         This package provides TemplateHaskell function to generate
                      instances of @Matchable@ and @Bimatchable@ type classes,
@@ -10,8 +10,10 @@
 maintainer:          viercc@gmail.com
 category:            Functors
 build-type:          Simple
-extra-source-files:  README.md, CHANGELOG.md
+extra-source-files:  README.md
+extra-doc-files:     CHANGELOG.md
 cabal-version:       2.0
+tested-with:         GHC ==9.0.2, GHC ==9.2.7, GHC ==9.4.4, GHC ==9.6.1
 
 source-repository head
   type:     git
@@ -23,7 +25,7 @@
   exposed-modules:      Data.Matchable.TH
   build-depends:        base               >= 4.10       && <5,
                         matchable          >= 0.1.2,
-                        template-haskell   >= 2.4 && < 2.18,
+                        template-haskell   >= 2.4 && < 2.21,
                         th-abstraction     >= 0.4.0.0
   ghc-options:          -Wall
   default-language:     Haskell2010
diff --git a/test/th.hs b/test/th.hs
--- a/test/th.hs
+++ b/test/th.hs
@@ -79,33 +79,54 @@
 
 -- Most simple case
 data BiF a b = BiF0 | BiF1 a b
+  deriving (Show, Eq)
 
 $(deriveBimatchable ''BiF)
 
+instance Eq a => Eq1 (BiF a) where
+  liftEq = liftEq2Default (==)
+
 instance Eq2 BiF where
   liftEq2 = liftEq2Default
 
+instance Functor (BiF a) where
+  fmap = bimapRecovered id
+
 instance Bifunctor BiF where
   bimap = bimapRecovered
 
 -- Test case for using [], tuple, and another Bimatchable instance
 data BiG a b = BiG0 | BiG1 [a] [b] | BiG2 (Int, BiF a b)
+  deriving (Show, Eq)
 
 $(deriveBimatchable ''BiG)
 
+instance Eq a => Eq1 (BiG a) where
+  liftEq = liftEq2Default (==)
+
 instance Eq2 BiG where
   liftEq2 = liftEq2Default
 
+instance Functor (BiG a) where
+  fmap = bimapRecovered id
+
 instance Bifunctor BiG where
   bimap = bimapRecovered
 
 -- Test case for recursive type
 data BiH a b = BiH1 a b | BiH2 (BiH b a) (BiH a String)
+  deriving (Show, Eq)
 
 $(deriveBimatchable ''BiH)
 
+instance Eq a => Eq1 (BiH a) where
+  liftEq = liftEq2Default (==)
+
 instance Eq2 BiH where
   liftEq2 = liftEq2Default
+
+instance Functor (BiH a) where
+  fmap = bimapRecovered id
 
 instance Bifunctor BiH where
   bimap = bimapRecovered