Security & setup Warnings

[MagnumGR]

I decide to uninstall NC10 from FC27 and install NC13.0.1 from your repository. When i check the Security & setup Warnings i saw :

Some files have not passed the integrity check. Further information on how to resolve this issue can be found in the documentation. (List of invalid files… / Rescan…)

No memory cache has been configured. To enhance performance, please configure a memcache, if available. Further information can be found in the documentation.
The PHP OPcache is not properly configured. For better performance it is recommended to use the following settings in the php.ini:

opcache.enable=1
opcache.enable_cli=1
opcache.interned_strings_buffer=8
opcache.max_accelerated_files=10000
opcache.memory_consumption=128
opcache.save_comments=1
opcache.revalidate_freq=1

Especially on 1st Warning see attached file : failed.txt

[MagnumGR]

Also there is a problem when updating an App like PDF Viewer from 1.2.0 to 1.2.1, or when you want to enable an App like Metadata etc. The problem is contacting to AppStore. When you download and manual install the App then you can Enable the App.

See Attached file the errors from NC log. Appstore.txt

[MagnumGR]

More detail from Log when i'm trying to update PDF viewer :

Error: Class 'Archive_Tar' not found

/usr/share/nextcloud/lib/private/Installer.php - line 286: OC\Archive\TAR->__construct('/tmp/oc_tmp_HTd...')
/usr/share/nextcloud/lib/private/Installer.php - line 196: OC\Installer->downloadApp('files_pdfviewer')
/usr/share/nextcloud/settings/ajax/updateapp.php - line 45: OC\Installer->updateAppstoreApp('files_pdfviewer')
/usr/share/nextcloud/lib/private/Route/Route.php - line 155: require_once('/usr/share/next...')
[internal function] OC\Route\Route->OC\Route\{closure}(*** sensitive parameters replaced ***)
/usr/share/nextcloud/lib/private/Route/Router.php - line 297: call_user_func(Object(Closure), Array)
/usr/share/nextcloud/lib/base.php - line 998: OC\Route\Router->match('/settings/ajax/...')
/usr/share/nextcloud/index.php - line 37: OC handleRequest()
{main}