diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 24e45e3..ba83636 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -17,6 +17,11 @@ jobs:
           - { php: 5.6, flags: --prefer-lowest }
           - { php: '7.0', flags: --prefer-lowest }
           - { php: 7.1, flags: --prefer-lowest }
+          # Explicitly exercise the sebastian/comparator 8.0 / 8.1 range — the
+          # versions that still lack the #158 serialization fix and therefore
+          # still need this patch (requires PHP >= 8.4).
+          - { php: 8.4, comparator: 8.0.* }
+          - { php: 8.5, comparator: 8.1.* }
 
     steps:
       - uses: actions/checkout@v3
@@ -26,7 +31,11 @@ jobs:
         with:
           php-version: ${{ matrix.php }}
 
-      - run: composer require phpunit/phpunit --dev ${{ matrix.flags }}
-      - run: composer show | grep -E '^(phpunit/phpunit|sebastian/comparator)'
+      - name: Pin sebastian/comparator
+        if: ${{ matrix.comparator }}
+        run: composer require "sebastian/comparator:${{ matrix.comparator }}" --no-update
+
+      - run: composer require phpunit/phpunit --dev ${{ matrix.flags }} ${{ matrix.comparator && '-W' || '' }}
+      - run: composer show | grep -E '^(phpunit/phpunit|sebastian/comparator|sebastian/diff)'
       - run: 'vendor/bin/phpunit --migrate-configuration || :'
       - run: vendor/bin/phpunit
diff --git a/README.md b/README.md
index 5def956..0ce9b8a 100644
--- a/README.md
+++ b/README.md
@@ -2,11 +2,16 @@
 
 Fixes `assertSame()`/`assertEquals()` serialization errors running in separate processes.
 
+> [!IMPORTANT]
+> **`sebastian/comparator` `8.2.0` fixes this upstream**, so this patch is only needed below that version.
+> See [sebastianbergmann/comparator#158](https://github.com/sebastianbergmann/comparator/issues/158): as of `8.2.0`, `ComparisonFailure` implements `__serialize()`/`__unserialize()` and can be serialized across process-isolation boundaries even when its stack trace references non-serializable objects (e.g. a `PDO` passed as a method argument) — exactly the case this package works around.
+> This package is therefore constrained to `sebastian/comparator` `<8.2`. On `comparator` `>=8.2` you do **not** need it (and shouldn't install it: it would override the upstream-fixed class).
+
 ## Requirements
 
 - php: `>=5.3.3`
 - [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit): `>=4.8.0`
-- [sebastianbergmann/comparator](https://github.com/sebastianbergmann/comparator): `^1.0 || ^2.0 || ^3.0 || ^4.0 || ^5.0 || ^6.0 || ^7.0`
+- [sebastianbergmann/comparator](https://github.com/sebastianbergmann/comparator): `^1.0 || ^2.0 || ^3.0 || ^4.0 || ^5.0 || ^6.0 || ^7.0 || >=8.0 <8.2`
 
 ## Installing
 
diff --git a/composer.json b/composer.json
index ebdc4ef..ee9b16f 100644
--- a/composer.json
+++ b/composer.json
@@ -9,7 +9,17 @@
             "email": "ryosuke_i_628@yahoo.co.jp"
         }
     ],
-    "keywords": ["phpunit", "isolation", "serialization", "separate", "process", "processes", "patch", "fix", "bug"],
+    "keywords": [
+        "phpunit",
+        "isolation",
+        "serialization",
+        "separate",
+        "process",
+        "processes",
+        "patch",
+        "fix",
+        "bug"
+    ],
     "autoload": {
         "files": [
             "./files/ComparisonFailure.php"
@@ -28,7 +38,7 @@
     },
     "require": {
         "php": ">=5.3.3",
-        "sebastian/comparator": "^1.0 || ^2.0 || ^3.0 || ^4.0 || ^5.0 || ^6.0 || ^7.0"
+        "sebastian/comparator": "^1.0 || ^2.0 || ^3.0 || ^4.0 || ^5.0 || ^6.0 || ^7.0 || >=8.0 <8.2"
     },
     "require-dev": {
         "phpunit/phpunit": ">=4.8"
diff --git a/files/ComparisonFailure.php b/files/ComparisonFailure.php
index 3c5b97c..ac1adc2 100644
--- a/files/ComparisonFailure.php
+++ b/files/ComparisonFailure.php
@@ -110,10 +110,26 @@ public function getDiff()
         }
 
         $header = "\n--- Expected\n+++ Actual\n";
+        $builder = $header;
         if (\class_exists('SebastianBergmann\Diff\Output\UnifiedDiffOutputBuilder')) {
-            $header = new UnifiedDiffOutputBuilder($header);
+            // sebastian/diff >=8 (pulled in by sebastian/comparator ^8) adds an
+            // `emitNoLineEndEofWarning` constructor argument that defaults to true,
+            // which injects `\ No newline at end of file` markers into the diff.
+            // Disable it when available to keep the legacy output format; older
+            // diff releases lack the argument, so fall back to the 1-argument form.
+            $emitsNoLineEndEofWarning = false;
+            $constructor = new \ReflectionMethod('SebastianBergmann\Diff\Output\UnifiedDiffOutputBuilder', '__construct');
+            foreach ($constructor->getParameters() as $parameter) {
+                if ($parameter->getName() === 'emitNoLineEndEofWarning') {
+                    $emitsNoLineEndEofWarning = true;
+                    break;
+                }
+            }
+            $builder = $emitsNoLineEndEofWarning
+                ? new UnifiedDiffOutputBuilder($header, false, 3, false)
+                : new UnifiedDiffOutputBuilder($header);
         }
-        $differ = new Differ($header);
+        $differ = new Differ($builder);
 
         return $differ->diff($this->expectedAsString, $this->actualAsString);
     }