diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index 8782c2ca..a47c1be0 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -24,6 +24,7 @@
 use OCA\AppAPI\Notifications\ExAppNotifier;
 use OCA\AppAPI\PublicCapabilities;
 use OCA\AppAPI\SetupChecks\DaemonCheck;
+use OCA\AppAPI\SetupChecks\HarpVersionCheck;
 use OCA\DAV\Events\SabrePluginAddEvent;
 use OCA\DAV\Events\SabrePluginAuthInitEvent;
 use OCA\Files\Event\LoadAdditionalScriptsEvent;
@@ -42,6 +43,7 @@ class Application extends App implements IBootstrap {
 	public const APP_ID = 'app_api';
 	public const TEST_DEPLOY_APPID = 'test-deploy';
 	public const TEST_DEPLOY_INFO_XML = 'https://raw.githubusercontent.com/nextcloud/test-deploy/main/appinfo/info.xml';
+	public const MINIMUM_HARP_VERSION = '0.3.0';
 
 	public function __construct(array $urlParams = []) {
 		parent::__construct(self::APP_ID, $urlParams);
@@ -69,6 +71,7 @@ public function register(IRegistrationContext $context): void {
 		$context->registerEventListener(DeclarativeSettingsSetValueEvent::class, SetValueListener::class);
 
 		$context->registerSetupCheck(DaemonCheck::class);
+		$context->registerSetupCheck(HarpVersionCheck::class);
 	}
 
 	public function boot(IBootContext $context): void {
diff --git a/lib/Service/HarpService.php b/lib/Service/HarpService.php
index 1e5fc753..979fe44c 100644
--- a/lib/Service/HarpService.php
+++ b/lib/Service/HarpService.php
@@ -106,7 +106,7 @@ public static function getExAppHost(ExApp $exApp): string {
 				return $exApp->getAppid();
 			}
 		}
-		return "127.0.0.1";
+		return '127.0.0.1';
 	}
 
 	public function getHarpExApp(ExApp $exApp): array {
@@ -157,4 +157,34 @@ public function harpExAppUpdate(DaemonConfig $daemonConfig, ExApp $exApp, bool $
 			$this->logger->error("HarpService: harpExAppUpdate ($addedStr) failed: " . $e->getMessage());
 		}
 	}
+
+	public function getHarpVersion(DaemonConfig $daemonConfig): ?string {
+		if (!self::isHarp($daemonConfig->getDeployConfig())) {
+			return null;
+		}
+		$this->initGuzzleClient($daemonConfig);
+		$url = $this->buildHarpUrl($daemonConfig, '/info');
+		$this->logger->info('HarpService: getHarpVersion: ' . $url);
+
+		try {
+			$response = $this->guzzleClient->get($url);
+			$data = json_decode($response->getBody()->getContents(), true);
+			if (isset($data['version'])) {
+				if (gettype($data['version']) === 'double') {
+					return $this->versionFloatToString($data['version']);
+				}
+				return (string) $data['version'];
+			}
+			return null;
+		} catch (\Exception $e) {
+			$this->logger->error('HarpService: getHarpVersion failed: ' . $e->getMessage());
+			return null;
+		}
+	}
+
+	private function versionFloatToString(float $version): string {
+		// If the Harp version was reported as a float, e.g. `4.2`, convert it to the string "4.2.0".
+		// We use number_format to avoid potential issues from locale-dependent float to string conversions.
+		return rtrim(number_format($version, 10, '.', ''), '0') . '.0';
+	}
 }
diff --git a/lib/SetupChecks/HarpVersionCheck.php b/lib/SetupChecks/HarpVersionCheck.php
new file mode 100644
index 00000000..fd7afc4b
--- /dev/null
+++ b/lib/SetupChecks/HarpVersionCheck.php
@@ -0,0 +1,103 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\AppAPI\SetupChecks;
+
+use OCA\AppAPI\AppInfo\Application;
+use OCA\AppAPI\Db\DaemonConfig;
+use OCA\AppAPI\Service\DaemonConfigService;
+use OCA\AppAPI\Service\HarpService;
+use OCP\ICacheFactory;
+use OCP\IL10N;
+use OCP\SetupCheck\ISetupCheck;
+use OCP\SetupCheck\SetupResult;
+use Psr\Log\LoggerInterface;
+
+class HarpVersionCheck implements ISetupCheck {
+	private ?\OCP\ICache $cache = null;
+
+	public function __construct(
+		private readonly IL10N               $l10n,
+		private readonly LoggerInterface     $logger,
+		private readonly DaemonConfigService $daemonConfigService,
+		private readonly HarpService         $harpService,
+		ICacheFactory                        $cacheFactory,
+	) {
+		if ($cacheFactory->isAvailable()) {
+			$this->cache = $cacheFactory->createDistributed(Application::APP_ID . '/harp_version_check');
+		}
+	}
+
+	public function getName(): string {
+		return $this->l10n->t('AppAPI HaRP version check');
+	}
+
+	public function getCategory(): string {
+		return 'system';
+	}
+
+	/**
+	 * @return DaemonConfig[]
+	 */
+	private function getHaRPDaemonConfigs(): array {
+		$allDaemons = $this->daemonConfigService->getRegisteredDaemonConfigs();
+		return array_filter($allDaemons, function (DaemonConfig $daemon) {
+			return HarpService::isHarp($daemon->getDeployConfig());
+		});
+	}
+
+	public function run(): SetupResult {
+		$harpDaemons = $this->getHaRPDaemonConfigs();
+
+		if (empty($harpDaemons)) {
+			return SetupResult::success();
+		}
+
+		$issues = [];
+		foreach ($harpDaemons as $daemonConfig) {
+			try {
+				$versionString = $this->getHarpVersion($daemonConfig);
+				if ($versionString === null) {
+					$issues[] = $this->l10n->t('Could not retrieve HaRP version from daemon "%s"', [$daemonConfig->getName()]);
+					continue;
+				}
+				if (!$this->fulfillsMinimumVersionRequirement($versionString)) {
+					$issues[] = $this->l10n->t('HaRP version for daemon "%s" is "%s", which is too old. The minimum required version is "%s". Please update the daemon to the latest version.', [$daemonConfig->getName(), $versionString, Application::MINIMUM_HARP_VERSION]);
+				}
+			} catch (\Exception $e) {
+				$this->logger->error('Failed to check HaRP version for daemon ' . $daemonConfig->getName() . ': ' . $e->getMessage(), ['exception' => $e]);
+				$issues[] = $this->l10n->t('Failed to check HaRP version for daemon "%s": %s', [$daemonConfig->getName(), $e->getMessage()]);
+			}
+		}
+
+		if (!empty($issues)) {
+			return SetupResult::warning(
+				implode("<br />", $issues),
+				'https://github.com/nextcloud/HaRP/',
+			);
+		}
+
+		return SetupResult::success();
+	}
+
+	private function fulfillsMinimumVersionRequirement(string $version): bool {
+		return version_compare($version, Application::MINIMUM_HARP_VERSION, '>=');
+	}
+
+	private function getHarpVersion(DaemonConfig $daemonConfig): ?string {
+		$cacheKey = $daemonConfig->getName() . '_' . (string)crc32(json_encode($daemonConfig));
+		$version = $this->cache?->get($cacheKey);
+		if ($version === null) {
+			$version = $this->harpService->getHarpVersion($daemonConfig);
+			$oneWeek = 60 * 60 * 24 * 7;
+			$this->cache?->set($cacheKey, $version, $oneWeek);
+		}
+		return $version;
+	}
+}