diff --git a/lib/modules/datasource/packagist/schema.spec.ts b/lib/modules/datasource/packagist/schema.spec.ts
index 2bae8ee23f0056..c673fa7281fd0e 100644
--- a/lib/modules/datasource/packagist/schema.spec.ts
+++ b/lib/modules/datasource/packagist/schema.spec.ts
@@ -2,13 +2,74 @@ import type { ReleaseResult } from '../types';
 import {
   ComposerRelease,
   ComposerReleases,
+  MinifiedArray,
   parsePackagesResponse,
   parsePackagesResponses,
 } from './schema';
 
 describe('modules/datasource/packagist/schema', () => {
+  describe('MinifiedArray', () => {
+    it('parses MinifiedArray', () => {
+      expect(MinifiedArray.parse([])).toEqual([]);
+
+      // Source: https://github.com/composer/metadata-minifier/blob/1.0.0/tests/MetadataMinifierTest.php
+      expect(
+        MinifiedArray.parse([
+          {
+            name: 'foo/bar',
+            version: '2.0.0',
+            version_normalized: '2.0.0.0',
+            type: 'library',
+            scripts: {
+              foo: 'bar',
+            },
+            license: ['MIT'],
+          },
+          {
+            version: '1.2.0',
+            version_normalized: '1.2.0.0',
+            license: ['GPL'],
+            homepage: 'https://example.org',
+            scripts: '__unset',
+          },
+          {
+            version: '1.0.0',
+            version_normalized: '1.0.0.0',
+            homepage: '__unset',
+          },
+        ])
+      ).toEqual([
+        {
+          name: 'foo/bar',
+          version: '2.0.0',
+          version_normalized: '2.0.0.0',
+          type: 'library',
+          scripts: {
+            foo: 'bar',
+          },
+          license: ['MIT'],
+        },
+        {
+          name: 'foo/bar',
+          version: '1.2.0',
+          version_normalized: '1.2.0.0',
+          type: 'library',
+          license: ['GPL'],
+          homepage: 'https://example.org',
+        },
+        {
+          name: 'foo/bar',
+          version: '1.0.0',
+          version_normalized: '1.0.0.0',
+          type: 'library',
+          license: ['GPL'],
+        },
+      ]);
+    });
+  });
+
   describe('ComposerRelease', () => {
-    it('rejects', () => {
+    it('rejects ComposerRelease', () => {
       expect(() => ComposerRelease.parse(null)).toThrow();
       expect(() => ComposerRelease.parse(undefined)).toThrow();
       expect(() => ComposerRelease.parse('')).toThrow();
@@ -17,7 +78,7 @@ describe('modules/datasource/packagist/schema', () => {
       expect(() => ComposerRelease.parse({ version: null })).toThrow();
     });
 
-    it('parses', () => {
+    it('parses ComposerRelease', () => {
       expect(ComposerRelease.parse({ version: '' })).toEqual({ version: '' });
       expect(ComposerRelease.parse({ version: 'dev-main' })).toEqual({
         version: 'dev-main',
@@ -50,14 +111,14 @@ describe('modules/datasource/packagist/schema', () => {
   });
 
   describe('ComposerReleases', () => {
-    it('rejects', () => {
+    it('rejects ComposerReleases', () => {
       expect(() => ComposerReleases.parse(null)).toThrow();
       expect(() => ComposerReleases.parse(undefined)).toThrow();
       expect(() => ComposerReleases.parse('')).toThrow();
       expect(() => ComposerReleases.parse({})).toThrow();
     });
 
-    it('parses', () => {
+    it('parses ComposerReleases', () => {
       expect(ComposerReleases.parse([])).toEqual([]);
       expect(ComposerReleases.parse([null])).toEqual([]);
       expect(ComposerReleases.parse([1, 2, 3])).toEqual([]);
@@ -69,7 +130,7 @@ describe('modules/datasource/packagist/schema', () => {
   });
 
   describe('parsePackageResponse', () => {
-    it('parses', () => {
+    it('parses package response', () => {
       expect(parsePackagesResponse('foo/bar', null)).toEqual([]);
       expect(parsePackagesResponse('foo/bar', {})).toEqual([]);
       expect(parsePackagesResponse('foo/bar', { packages: '123' })).toEqual([]);
@@ -86,7 +147,7 @@ describe('modules/datasource/packagist/schema', () => {
   });
 
   describe('parsePackagesResponses', () => {
-    it('parses', () => {
+    it('parses array of responses', () => {
       expect(parsePackagesResponses('foo/bar', [null])).toBeNull();
       expect(parsePackagesResponses('foo/bar', [{}])).toBeNull();
       expect(
diff --git a/lib/modules/datasource/packagist/schema.ts b/lib/modules/datasource/packagist/schema.ts
index 881b0012579964..3a998becb62f8a 100644
--- a/lib/modules/datasource/packagist/schema.ts
+++ b/lib/modules/datasource/packagist/schema.ts
@@ -1,7 +1,44 @@
+import is from '@sindresorhus/is';
 import { z } from 'zod';
 import { logger } from '../../../logger';
 import type { Release, ReleaseResult } from '../types';
 
+export const MinifiedArray = z.array(z.record(z.unknown())).transform((xs) => {
+  // Ported from: https://github.com/composer/metadata-minifier/blob/main/src/MetadataMinifier.php#L17
+  if (xs.length === 0) {
+    return xs;
+  }
+
+  const prevVals: Record<string, unknown> = {};
+  for (const x of xs) {
+    for (const key of Object.keys(x)) {
+      prevVals[key] ??= undefined;
+    }
+
+    for (const key of Object.keys(prevVals)) {
+      const val = x[key];
+      if (val === '__unset') {
+        delete x[key];
+        prevVals[key] = undefined;
+        continue;
+      }
+
+      if (!is.undefined(val)) {
+        prevVals[key] = val;
+        continue;
+      }
+
+      if (!is.undefined(prevVals[key])) {
+        x[key] = prevVals[key];
+        continue;
+      }
+    }
+  }
+
+  return xs;
+});
+export type MinifiedArray = z.infer<typeof MinifiedArray>;
+
 export const ComposerRelease = z
   .object({
     version: z.string(),
@@ -37,7 +74,8 @@ export function parsePackagesResponse(
 ): ComposerReleases {
   try {
     const { packages } = ComposerPackagesResponse.parse(packagesResponse);
-    const releases = ComposerReleases.parse(packages[packageName]);
+    const array = MinifiedArray.parse(packages[packageName]);
+    const releases = ComposerReleases.parse(array);
     return releases;
   } catch (err) {
     logger.debug(