You most certainly can!
Login to your cloud and in the right corner drop-down menu select “Upgrade“.

Alternatively, you can visit clients.webo.hosting and order Nextcloud Package upgrade.
To upgrade visit:
https://clients.webo.hosting/cart.php?a=add&pid=501
If you wish to upgrade Family, Business, VPS or Dedicated please log in to clients.webo.hosting and under “Products” select upgrade. Or you can read here on how to do it “Upgrade my Nextcloud Service.
