3 files changed, 4 insertions, 8 deletions
diff --git a/lib/private/App/AppManager.php b/lib/private/App/AppManager.php
index 0e921ba1b7f..ede1e5a7fa7 100644
--- a/lib/private/App/AppManager.php
+++ b/lib/private/App/AppManager.php
@@ -380,10 +380,10 @@ class AppManager implements IAppManager {
 		return $data;
 	}
 
-	public function getAppVersion(string $appId, bool $useCache = true) {
+	public function getAppVersion(string $appId, bool $useCache = true): string {
 		if(!$useCache || !isset($this->appVersions[$appId])) {
 			$appInfo = \OC::$server->getAppManager()->getAppInfo($appId);
-			$this->appVersions[$appId] = ($appInfo !== null) ? $appInfo['version'] : '0';
+			$this->appVersions[$appId] = ($appInfo !== null && isset($appInfo['version'])) ? $appInfo['version'] : '0';
 		}
 		return $this->appVersions[$appId];
 	}
diff --git a/lib/private/Installer.php b/lib/private/Installer.php
index f382a923401..8a8ece82077 100644
--- a/lib/private/Installer.php
+++ b/lib/private/Installer.php
@@ -112,7 +112,7 @@ class Installer {
 			);
 		}
 
-		$version = \OCP\Util::getVersion();
+		$version = implode('.', \OCP\Util::getVersion());
 		if (!\OC_App::isAppCompatible($version, $info)) {
 			throw new \Exception(
 				// TODO $l
diff --git a/lib/private/legacy/app.php b/lib/private/legacy/app.php
index f04310041ac..40af10f36fc 100644
--- a/lib/private/legacy/app.php
+++ b/lib/private/legacy/app.php
@@ -856,7 +856,7 @@ class OC_App {
 	 *
 	 * @return boolean true if compatible, otherwise false
 	 */
-	public static function isAppCompatible($ocVersion, $appInfo) {
+	public static function isAppCompatible(string $ocVersion, array $appInfo): bool {
 		$requireMin = '';
 		$requireMax = '';
 		if (isset($appInfo['dependencies']['nextcloud']['@attributes']['min-version'])) {
@@ -877,10 +877,6 @@ class OC_App {
 			$requireMax = $appInfo['requiremax'];
 		}
 
-		if (is_array($ocVersion)) {
-			$ocVersion = implode('.', $ocVersion);
-		}
-
 		if (!empty($requireMin)
 			&& version_compare(self::adjustVersionParts($ocVersion, $requireMin), $requireMin, '<')
 		) {