diff --git a/.github/workflows/hidrive-next-build.yml b/.github/workflows/hidrive-next-build.yml
index dfa0cf7443049..4003a91762670 100644
--- a/.github/workflows/hidrive-next-build.yml
+++ b/.github/workflows/hidrive-next-build.yml
@@ -120,6 +120,15 @@ jobs:
       - name: Add config partials
         run: make -f IONOS/Makefile add_config_partials
 
+      # IONOS Customization: Inject build number for production traceability
+      # This is specific to IONOS HiDrive Next and not part of upstream Nextcloud
+      - name: Inject build number
+        run: |
+          echo "${{ github.run_number }}" > .buildnumber
+          echo "✅ Build number injected: ${{ github.run_number }}"
+          echo "📄 File created: .buildnumber"
+          cat .buildnumber
+
       - name: Zip dependencies
         run: make -f IONOS/Makefile zip_dependencies TARGET_PACKAGE_NAME=${{ env.TARGET_PACKAGE_NAME }}
 
diff --git a/.gitignore b/.gitignore
index db05c7794b98e..400a0d0141633 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,6 +15,9 @@
 /translationfiles
 /translationtool.phar
 
+# CI/CD generated files
+/.buildnumber
+
 # ignore all apps except core ones
 /apps*/*
 !/apps/cloud_federation_api
diff --git a/version.php b/version.php
index 0cce4c8340e43..a6c560befc230 100644
--- a/version.php
+++ b/version.php
@@ -32,3 +32,51 @@
 
 // Vendor of this package
 $vendor = 'nextcloud';
+
+// ============================================================================
+// CI/CD Build Number Injection (IONOS Nextcloud Workspace)
+// ============================================================================
+// Injects a 5th element into the $OC_Version array from the .buildnumber file.
+// This file is automatically created by the CI/CD pipeline (build-artifact.yml)
+// and contains the GitHub workflow run ID for traceability.
+//
+// NOTE: This is an IONOS-specific customization for Nextcloud Workspace.
+//       It is not part of upstream Nextcloud and is used for tracking
+//       IONOS Nextcloud Workspace builds in production environments.
+//
+// @since 31.0.8
+//
+// Purpose:
+//   - Track which specific CI/CD run produced this artifact
+//   - Enable direct linking to workflow logs and build details
+//   - Distinguish between different builds of the same version
+//   - Support debugging by identifying exact build in production
+//
+// File Format:
+//   .buildnumber - Single line containing an integer (GitHub run ID)
+//   Example: 12345678901
+//
+// Result:
+//   Without .buildnumber: $OC_Version = [31, 0, 8, 1]
+//   With .buildnumber:    $OC_Version = [31, 0, 8, 1, 12345678901]
+//
+// Accessed via:
+//   - ServerVersion::getBuildId() -> 12345678901
+//   - ServerVersion::getHumanVersion() -> "31.0.8 (12345678901)"
+//   - ServerVersion::getVersion() -> [31, 0, 8, 1, 12345678901]
+//
+// Workflow URL Construction:
+//   https://github.com/{org}/{repo}/actions/runs/{buildId}
+//
+// ============================================================================
+$buildNumberFile = __DIR__ . '/.buildnumber';
+if (file_exists($buildNumberFile)) {
+	$buildNumberContent = @file_get_contents($buildNumberFile);
+	if ($buildNumberContent !== false) {
+		$buildId = (int)trim($buildNumberContent);
+		if ($buildId > 0) {
+			// Append build ID as 5th element in version array
+			$OC_Version[] = $buildId;
+		}
+	}
+}