diff --git a/lib/Migration/Version1Date20260901000000.php b/lib/Migration/Version1Date20260901000000.php
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+<?php
+
+/**
+ * Re-run of the PostgreSQL `pg_trgm` extension bootstrap.
+ *
+ * Version1Date20260706110000 already installs `pg_trgm` — but that file's
+ * `CREATE EXTENSION IF NOT EXISTS pg_trgm` call was added on 2026-07-21
+ * (openregister commit 15d93450a3c), *after* the migration had already
+ * shipped and been recorded as run on existing installations. Nextcloud's
+ * migrator only executes each `app+version` row once, so instances that
+ * ran the older empty version of the file never install the extension —
+ * and `MagicSearchHandler::hasPgTrgmExtension()` correctly reports false,
+ * so `_fuzzy=true` silently degrades to unindexed ILIKE and never sets
+ * `@self.relevance`. Symptom: fuzzy typo-tolerance and relevance-scoring
+ * broken on any instance upgraded through the intermediate window.
+ *
+ * This migration is a NEW `app+version` row that re-runs the same
+ * idempotent `CREATE EXTENSION IF NOT EXISTS pg_trgm` on every instance.
+ * Same tolerant-failure contract as Version1Date20260706110000 —
+ * privilege denial is logged, never fatal.
+ *
+ * SPDX-License-Identifier: EUPL-1.2
+ * SPDX-FileCopyrightText: 2026 Conduction B.V.
+ *
+ * @category Migration
+ * @package  OCA\OpenRegister\Migration
+ *
+ * @author    Conduction Development Team <dev@conduction.nl>
+ * @copyright 2026 Conduction B.V.
+ * @license   EUPL-1.2 https://joinup.ec.europa.eu/collection/eupl/eupl-text-eupl-12
+ *
+ * @link https://OpenRegister.app
+ */
+
+declare(strict_types=1);
+
+namespace OCA\OpenRegister\Migration;
+
+use Closure;
+use Exception;
+use OCP\IDBConnection;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+/**
+ * Re-runs `CREATE EXTENSION IF NOT EXISTS pg_trgm` on PostgreSQL.
+ *
+ * @package OCA\OpenRegister\Migration
+ *
+ * @spec openspec/changes/searchable-property-index/tasks.md#1.1
+ */
+class Version1Date20260901000000 extends SimpleMigrationStep {
+	/**
+	 * Constructor.
+	 *
+	 * @param IDBConnection $connection Database connection
+	 */
+	public function __construct(
+		private readonly IDBConnection $connection,
+	) {
+	}//end __construct()
+
+	/**
+	 * Ensure the pg_trgm extension exists after schema changes (PostgreSQL only).
+	 *
+	 * @param IOutput $output Migration output
+	 * @param Closure $schemaClosure Schema closure
+	 * @param array $options Migration options
+	 *
+	 * @return void
+	 *
+	 * @spec openspec/changes/searchable-property-index/tasks.md#1.1
+	 */
+	public function postSchemaChange(IOutput $output, Closure $schemaClosure, array $options): void {
+		$platform = $this->connection->getDatabasePlatform();
+
+		if (str_contains(get_class($platform), 'PostgreSQL') === false) {
+			$output->info('Skipping pg_trgm extension re-bootstrap: unsupported database platform (PostgreSQL only)');
+			return;
+		}
+
+		$this->ensurePgTrgmExtension(output: $output);
+	}//end postSchemaChange()
+
+	/**
+	 * Create the pg_trgm extension when missing, tolerating privilege failures.
+	 *
+	 * Same contract as Version1Date20260706110000::ensurePgTrgmExtension —
+	 * `CREATE EXTENSION IF NOT EXISTS` is idempotent, and a privilege
+	 * failure is logged rather than fatal so the migration is safe on
+	 * instances where the extension is already present or where the
+	 * connecting role lacks the CREATE EXTENSION privilege.
+	 *
+	 * Probes `pg_extension` before the CREATE EXTENSION call so the log
+	 * distinguishes the no-op re-run (extension was already installed by the
+	 * 2026-07 bootstrap or an operator) from the actual install that this
+	 * re-run migration ships to perform on instances that missed the first run.
+	 *
+	 * @param IOutput $output Migration output
+	 *
+	 * @return void
+	 */
+	private function ensurePgTrgmExtension(IOutput $output): void {
+		try {
+			$wasAlreadyInstalled = false;
+			try {
+				$result = $this->connection->executeQuery(
+					"SELECT 1 FROM pg_extension WHERE extname = 'pg_trgm'"
+				);
+				$wasAlreadyInstalled = ($result->fetchOne() !== false);
+			} catch (Exception $probeException) {
+				// Probe failed (e.g. permissions on pg_extension); fall through to
+				// the CREATE EXTENSION attempt, which is idempotent regardless.
+			}
+
+			$this->connection->executeStatement('CREATE EXTENSION IF NOT EXISTS pg_trgm');
+			if ($wasAlreadyInstalled === true) {
+				$output->info('pg_trgm extension already installed (no-op re-run)');
+			} else {
+				$output->info('pg_trgm extension installed by re-run (fuzzy/substring search indexes can now be created)');
+			}
+
+			return;
+		} catch (Exception $e) {
+			// Creation failed (usually privileges); check whether it already exists.
+			try {
+				$result = $this->connection->executeQuery(
+					"SELECT 1 FROM pg_extension WHERE extname = 'pg_trgm'"
+				);
+				if ($result->fetchOne() !== false) {
+					$output->info('pg_trgm extension already installed');
+					return;
+				}
+			} catch (Exception $inner) {
+				// Fall through to the warning below.
+			}
+
+			$output->warning(
+				'pg_trgm extension is not installed and could not be created ('
+				. $e->getMessage()
+				. '). Fuzzy/substring search (_fuzzy=true, @self.relevance) stays on '
+				. 'the unindexed ILIKE path. '
+				. 'Run CREATE EXTENSION pg_trgm; as a superuser and re-run this migration to enable it.'
+			);
+		}//end try
+	}//end ensurePgTrgmExtension()
+}//end class