You should upload the installer of Board3 Portal 2.0.2 and use its uninstall feature.

Das ist leider so zur Zeit nicht möglich. Entweder die linke/rechte Seite des Portals wird auf allen Seiten angezeigt, oder man nutzt nur das standardmäßige Portal.

This website still uses Board3 Portal 2.0.x.

This is due to caching of the portal. The next version will have a shorter cache time of only 30 seconds which will prevent any such long delay while also reducing the load on larger sites.

Again, the portal is supposed to look that way. It prevents you from having to zoom in to actually see the page.
This is expected behavior and frankly there is nothing to fix here.

Das ist leider bei Board3 Portal 2.0.x mit phpBB 3.0.x nicht möglich.
Bei Verwendung des neuen Portals 2.1.x für phpBB 3.1.x können hingegen die Module Bekanntmachungen, Hauptmenü, Links, News und natürlich Eigene Blöcke mehrfach hinzugefügt werden.

This site doesn't use the 2.1.0-RC versions yet. As I previously said, the way it looks on your website is the expected behavior and is part of the new responsiveness of the portal.

The screenshot you posted is the expected behavior for small screens.

If you want to update the portal with a newer version, just disable it in the ACP (do not delete the data), remove the existing files and upload the new ones, and enable the portal again in the ACP.

I'd recommend you just download the latest build from here: https://download.m-a-styles.de/2.1.x/la ... tal_73.zip

This does also apply to Board3 Portal 2.1.x: http://board3.de/knowledge/kb_show.php?id=61

This is a known issue and is currently being looked at here: http://board3.de/tracker.php?p=13&t=239

Changing it to display the complete topic would require a completely new module. The news module will not be capable of displaying a complete topic by modifying a few lines of code.

Please elaborate what you mean with display all posts. Are you thinking about specifying a specific post or do you want to show the complete topic on the portal?

It looks like you updated from phpBB 3.0.x & Board3 Portal 2.0.x t to phpBB 3.1.x & Board3 Portal 2.1.x without properly removing the Board3 Portal Modification before updating. Please take a look at this wiki article: https://github.com/board3/Board3-Portal/wiki/Updating-Board3-Portal-2.0.x...