UPDATE 2/4/2021: I adjusted my configuration so that upgrading to 6.x would not cause any issues anymore. Read more on how to upgrade the Unifi Controller manually on your Raspberry Pi
Please don’t update your Unifi controller to 6.0.xx
You will lose a couple great features that might mess up your network. Especially if you used the setup guide by The Hook Up. Think your VLAN settings for your WLAN and WLAN override configurations.
If you have already done this and regret it: follow the steps below to return to your previous settings.
So step 1 is: make sure you have scheduled backups turned on, else it’s too late anyway…
Then SSH into your controller
ssh {user}@{controller-ip} and enter your password.
Then enter the following commands one by one (no worries, your internet will keep working as we are only touching the controller)
apt purge unifi -y
rm unifi_sysvinit_all.deb*
wget https://dl.ui.com/unifi/5.14.23/unifi_sysvinit_all.deb
dpkg -i unifi_sysvinit_all.deb
rm unifi_sysvinit_all.deb
Then visit the controller via https://localhost:8443 or https://{controller-ip}:8443. here you can restore from your backup by uploading the file