diff --git a/unicode-data/test/Unicode/CharSpec.hs b/unicode-data/test/Unicode/CharSpec.hs
index 91461779..6c6bd895 100644
--- a/unicode-data/test/Unicode/CharSpec.hs
+++ b/unicode-data/test/Unicode/CharSpec.hs
@@ -6,7 +6,9 @@ module Unicode.CharSpec
   ( spec
   ) where
 
+import Data.Bits (Bits(..))
 import qualified Data.Char as Char
+import Data.Foldable (traverse_)
 import Data.Ix (Ix(..))
 import Data.Maybe (isJust)
 import qualified Unicode.Char as UChar
@@ -20,8 +22,27 @@ import qualified Unicode.Char.Case.Compat as UCharCompat
 import qualified Unicode.Char.Numeric as UNumeric
 import qualified Unicode.Char.Numeric.Compat as UNumericCompat
 import qualified Unicode.Internal.Char.UnicodeData.GeneralCategory as UC
-import Data.Foldable (traverse_)
 import Test.Hspec
+-- Use to display warnings. See note in `shouldBeEqualToV`.
+import Debug.Trace (traceM)
+
+#if MIN_VERSION_base(4,15,0)
+import Data.Version (showVersion)
+import GHC.Unicode (unicodeVersion)
+
+hasGhcUnicodeVersion :: Bool
+hasGhcUnicodeVersion = True
+
+#else
+import Data.Version (Version, makeVersion, showVersion)
+
+-- | Dummy Unicode version.
+unicodeVersion :: Version
+unicodeVersion = makeVersion [0, 0, 0]
+
+hasGhcUnicodeVersion :: Bool
+hasGhcUnicodeVersion = False
+#endif
 
 {- [NOTE]
 These tests may fail if the compiler’s Unicode version
@@ -36,22 +57,15 @@ does not match the version of this package.
 | 9.0.[1-2]   | 4.15.0         | 12.1            |
 | 9.2.[1-6]   | 4.16.0         | 14.0            |
 | 9.4.[1-4]   | 4.17.0         | 14.0            |
-| 9.6.1       | 4.18.0         | 15.0            |
+| 9.6.[1-3]   | 4.18.{0,1}     | 15.0            |
+| 9.6.4-5     | 4.18.2+        | 15.1            |
 | 9.8.1       | 4.19.0         | 15.1            |
+| 9.10.1      | 4.20.0         | 15.1            |
 +-------------+----------------+-----------------+
 -}
 
 spec :: Spec
 spec = do
-#ifdef COMPATIBLE_GHC_UNICODE
-  let describe' = describe
-  let it' = it
-#else
-  let describe' t = before_ (pendingWith "Incompatible GHC Unicode version")
-                  . describe t
-  let it' t = before_ (pendingWith "Incompatible GHC Unicode version")
-            . it t
-#endif
   describe "Unicode blocks" do
     it "Characters not in any block are unassigned"
         let { check c = case UBlocks.block c of
@@ -73,20 +87,20 @@ spec = do
     it "Characters in a block definition have the corresponding block"
         let {
             check b = let r = UBlocks.blockRange (UBlocks.blockDefinition b)
-                      in traverse_ (checkChar b) (UChar.chr <$> range r);
+                      in traverse_ (checkChar b. UChar.chr) (range r);
             checkChar b c = let b' = UBlocks.block c in if b' == Just b
                 then pure ()
                 else expectationFailure $ mconcat
                     [ "Block is different for “", show c, "”. Expected: “Just "
                     , show b, "” but got: “", show b', "”." ]
         } in traverse_ check [minBound..maxBound]
-  describe' "Unicode general categories" do
+  describe "Unicode general categories" do
     it "generalCategory" do
       -- [NOTE] We cannot compare the categories directly, so use 'show'.
-      (show . UChar.generalCategory) `shouldBeEqualTo` (show . Char.generalCategory)
-  describe' "Character classification" do
+      (show . UChar.generalCategory) `shouldBeEqualToV` (show . Char.generalCategory)
+  describe "Character classification" do
     it "isAlpha" do
-      UChar.isAlpha `shouldBeEqualTo` Char.isAlpha
+      UChar.isAlpha `shouldBeEqualToV` Char.isAlpha
     describe "isAlphaNum" do
       let isAlphaNumRef = \case
                         UChar.UppercaseLetter -> True
@@ -102,9 +116,9 @@ spec = do
         Char.chr UC.MaxIsAlphaNum `shouldBe` maxCodePointBy isAlphaNumRef
         UC.MaxIsAlphaNum `shouldSatisfy` isPlane0To3
       it "Compare to base" do
-        UChar.isAlphaNum `shouldBeEqualTo` Char.isAlphaNum
+        UChar.isAlphaNum `shouldBeEqualToV` Char.isAlphaNum
     it "isControl" do
-      UChar.isControl `shouldBeEqualTo` Char.isControl
+      UChar.isControl `shouldBeEqualToV` Char.isControl
     describe "isLetter" do
       let isLetterRef = \case
                         UChar.UppercaseLetter -> True
@@ -117,13 +131,13 @@ spec = do
         Char.chr UC.MaxIsLetter `shouldBe` maxCodePointBy isLetterRef
         UC.MaxIsLetter `shouldSatisfy` isPlane0To3
       it "Compare to base" do
-        UCharCompat.isLetter `shouldBeEqualTo` Char.isLetter
+        UCharCompat.isLetter `shouldBeEqualToV` Char.isLetter
     it "isMark" do
-      UChar.isMark `shouldBeEqualTo` Char.isMark
+      UChar.isMark `shouldBeEqualToV` Char.isMark
     it "isPrint" do
-      UChar.isPrint `shouldBeEqualTo` Char.isPrint
+      UChar.isPrint `shouldBeEqualToV` Char.isPrint
     it "isPunctuation" do
-      UChar.isPunctuation `shouldBeEqualTo` Char.isPunctuation
+      UChar.isPunctuation `shouldBeEqualToV` Char.isPunctuation
     describe "isSeparator" do
       it "Check max codepoint for isSeparator" do
         let isSeparatorRef = \case
@@ -134,27 +148,27 @@ spec = do
         Char.chr UC.MaxIsSeparator `shouldBe` maxCodePointBy isSeparatorRef
         UC.MaxIsSeparator `shouldSatisfy` isPlane0To3
       it "Compare to base" do
-        UChar.isSeparator `shouldBeEqualTo` Char.isSeparator
+        UChar.isSeparator `shouldBeEqualToV` Char.isSeparator
     describe "isSpace" do
       it "Check max codepoint for Space" do
         let isSpaceRef = (== UChar.Space)
         Char.chr UC.MaxIsSpace `shouldBe` maxCodePointBy isSpaceRef
         UC.MaxIsSpace `shouldSatisfy` isPlane0To3
       it "Compare to base" do
-        UCharCompat.isSpace `shouldBeEqualTo` Char.isSpace
+        UCharCompat.isSpace `shouldBeEqualToV` Char.isSpace
     it "isSymbol" do
-      UChar.isSymbol `shouldBeEqualTo` Char.isSymbol
+      UChar.isSymbol `shouldBeEqualToV` Char.isSymbol
   describe "Case" do
     describe "isLower" do
       it "Check max codepoint for lower" do
         let isLowerRef = (== UChar.LowercaseLetter)
         Char.chr UC.MaxIsLower `shouldBe` maxCodePointBy isLowerRef
         UC.MaxIsLower `shouldSatisfy` isPlane0To3
-      it' "Compare to base" do
-          UCharCompat.isLower `shouldBeEqualTo` Char.isLower
+      it "Compare to base" do
+          UCharCompat.isLower `shouldBeEqualToV` Char.isLower
 #if MIN_VERSION_base(4,18,0)
-    it' "isLowerCase" do
-      UChar.isLowerCase `shouldBeEqualTo` Char.isLowerCase
+    it "isLowerCase" do
+      UChar.isLowerCase `shouldBeEqualToV` Char.isLowerCase
 #endif
     describe "isUpper" do
       it "Check max codepoint for upper" do
@@ -164,14 +178,14 @@ spec = do
                             _                     -> False
         Char.chr UC.MaxIsUpper `shouldBe` maxCodePointBy isUpperRef
         UC.MaxIsUpper `shouldSatisfy` isPlane0To3
-      it' "Compare to base" do
-        UCharCompat.isUpper `shouldBeEqualTo` Char.isUpper
+      it "Compare to base" do
+        UCharCompat.isUpper `shouldBeEqualToV` Char.isUpper
 #if MIN_VERSION_base(4,18,0)
-    it' "isUpperCase" do
-      UChar.isUpperCase `shouldBeEqualTo` Char.isUpperCase
+    it "isUpperCase" do
+      UChar.isUpperCase `shouldBeEqualToV` Char.isUpperCase
 #endif
-    it' "toLower" do
-      UChar.toLower `shouldBeEqualTo` Char.toLower
+    it "toLower" do
+      UChar.toLower `shouldBeEqualToV` Char.toLower
     let caseCheck f (c, cs) = c `shouldSatisfy` (== cs) . f
     describe "toLowerString" do
         it "Examples" do
@@ -181,7 +195,7 @@ spec = do
                            , ('1', "1")
                            , ('\x130', "i\x307") ]
             traverse_ (caseCheck UChar.toLowerString) examples
-        it' "Common mapping should match simple one" do
+        it "Common mapping should match simple one" do
             let check c = case UChar.toLowerString c of
                         [c'] -> c `shouldSatisfy` ((== c') . UChar.toLower)
                         _    -> pure ()
@@ -191,8 +205,8 @@ spec = do
                     let cf = UChar.toLowerString c'
                     in cf == foldMap UChar.toLowerString cf
             traverse_ check [minBound..maxBound]
-    it' "toUpper" do
-      UChar.toUpper `shouldBeEqualTo` Char.toUpper
+    it "toUpper" do
+      UChar.toUpper `shouldBeEqualToV` Char.toUpper
     describe "toUpperString" do
         it "Examples" do
             let examples = [ ('\0', "\0")
@@ -202,7 +216,7 @@ spec = do
                            , ('\xdf', "SS")
                            , ('\x1F52', "\x03A5\x0313\x0300") ]
             traverse_ (caseCheck UChar.toUpperString) examples
-        it' "Common mapping should match simple one" do
+        it "Common mapping should match simple one" do
             let check c = case UChar.toUpperString c of
                         [c'] -> c `shouldSatisfy` ((== c') . UChar.toUpper)
                         _    -> pure ()
@@ -212,8 +226,8 @@ spec = do
                     let cf = UChar.toUpperString c'
                     in cf == foldMap UChar.toUpperString cf
             traverse_ check [minBound..maxBound]
-    it' "toTitle" do
-      UChar.toTitle `shouldBeEqualTo` Char.toTitle
+    it "toTitle" do
+      UChar.toTitle `shouldBeEqualToV` Char.toTitle
     describe "toTitleString" do
         it "Examples" do
             let examples = [ ('\0', "\0")
@@ -224,7 +238,7 @@ spec = do
                            , ('\xfb02', "Fl")
                            , ('\x1F52', "\x03A5\x0313\x0300") ]
             traverse_ (caseCheck UChar.toTitleString) examples
-        it' "Common mapping should match simple one" do
+        it "Common mapping should match simple one" do
             let check c = case UChar.toTitleString c of
                         [c'] -> c `shouldSatisfy` ((== c') . UChar.toTitle)
                         _    -> pure ()
@@ -253,8 +267,8 @@ spec = do
                             _                   -> False
         Char.chr UC.MaxIsNumber `shouldBe` maxCodePointBy isNumber
         UC.MaxIsNumber `shouldSatisfy` isPlane0To3
-      it' "Compare to base" do
-        UNumericCompat.isNumber `shouldBeEqualTo` Char.isNumber
+      it "Compare to base" do
+        UNumericCompat.isNumber `shouldBeEqualToV` Char.isNumber
     it "isNumber implies a numeric value" do
       -- [NOTE] the following does not hold with the current predicate `isNumber`.
       --        As of Unicode 15.0.0, there are 81 such characters (all CJK).
@@ -262,14 +276,71 @@ spec = do
       let check c = not (UNumericCompat.isNumber c) || isJust (UNumeric.numericValue c)
       traverse_ (`shouldSatisfy` check) [minBound..maxBound]
   where
-    shouldBeEqualTo
-        :: forall a b. (Bounded a, Enum a, Show a, Eq b, Show b)
-        => (a -> b)
-        -> (a -> b)
+    -- [NOTE] Unused for now
+    -- shouldBeEqualTo
+    --     :: forall a b. (Bounded a, Enum a, Show a, Eq b, Show b)
+    --     => (a -> b)
+    --     -> (a -> b)
+    --     -> IO ()
+    -- shouldBeEqualTo f g =
+    --     let same x = f x == g x
+    --     in traverse_ (`shouldSatisfy` same) [minBound..maxBound]
+
+    -- There is no feature to display warnings other than `trace`.
+    -- If we use `pendingWith` then the whole test is pending, not just
+    -- the assertion.
+    shouldBeEqualToV
+        :: forall b. (HasCallStack) => (Eq b, Show b)
+        => (Char -> b)
+        -> (Char -> b)
         -> IO ()
-    shouldBeEqualTo f g =
+    shouldBeEqualToV f g =
         let same x = f x == g x
-        in traverse_ (`shouldSatisfy` same) [minBound..maxBound]
+        in traverse_ (`shouldSatisfyV` same) [minBound..maxBound]
+
+    shouldSatisfyV :: (HasCallStack) => Char -> (Char -> Bool) -> IO ()
+    shouldSatisfyV c h
+        | hasSameUnicodeVersion = shouldSatisfy c h
+        | h c = pure ()
+        | not hasGhcUnicodeVersion = traceM . mconcat $
+            [ "[WARNING] Cannot test ", show c
+            , ": incompatible Unicode version (too old). Expected "
+            , showVersion UChar.unicodeVersion ]
+        | isUnassigned c = traceM . mconcat $
+            [ "[WARNING] Cannot test ", show c
+            , ": incompatible Unicode version (unassigned char). Expected "
+            , showVersion UChar.unicodeVersion
+            , ", but got: "
+            , showVersion unicodeVersion ]
+        | hasDifferentCategory c = traceM . mconcat $
+            [ "[WARNING] Cannot test ", show c
+            , ": incompatible Unicode version (different general category)."
+            , " Expected "
+            , showVersion UChar.unicodeVersion
+            , ", but got: "
+            , showVersion unicodeVersion ]
+        | otherwise = shouldSatisfy c h
+    -- Check if the character is not assigned in exactly one Unicode version.
+    isUnassigned c = (UChar.generalCategory c == UChar.NotAssigned)
+               `xor` (Char.generalCategory c == Char.NotAssigned)
+    -- Check if the character has changed its general category
+    hasDifferentCategory c = fromEnum (UChar.generalCategory c)
+                          /= fromEnum (Char.generalCategory c)
+    hasSameUnicodeVersion = unicodeVersion == UChar.unicodeVersion
+
+    -- [NOTE] Unused for now
+    -- shouldBe' x y
+    --     | x == y = pure ()
+    --     | unicodeVersion /= UChar.unicodeVersion = traceM msg
+    --     | otherwise = shouldBe x y
+    --     where
+    --     msg = mconcat
+    --         [ "[WARNING] Cannot test ", show x
+    --         , ": incompatible Unicode version. Expected "
+    --         , showVersion UChar.unicodeVersion
+    --         , ", but got: "
+    --         , unicodeVersionString ]
+
     isPlane0To3 = (< 0x40000)
     maxCodePointBy p = foldr
         (\c -> if p (UChar.generalCategory c) then max c else id)
diff --git a/unicode-data/unicode-data.cabal b/unicode-data/unicode-data.cabal
index c044e63c..243cdf85 100644
--- a/unicode-data/unicode-data.cabal
+++ b/unicode-data/unicode-data.cabal
@@ -124,10 +124,6 @@ test-suite test
       base             >= 4.7   && < 4.21
     , hspec            >= 2.0   && < 2.12
     , unicode-data
-  -- We need to match a GHC version with the same Unicode version.
-  -- See: test/Unicode/CharSpec.hs for compatibility table.
-  if impl(ghc >= 9.6.0) && impl(ghc < 9.8.0)
-    cpp-options: -DCOMPATIBLE_GHC_UNICODE
 
 benchmark bench
   import: default-extensions, compile-options